How to get the device's IMEI/ESN programmatically in android?

To identify each devices uniquely I would like to use the IMEI (or ESN number for CDMA devices). How to access this programmatically?

You want to call android.telephony.TelephonyManager.getDeviceId().

This will return whatever string uniquely identifies the device (IMEI on GSM, MEID for CDMA).

You'll need the following permission in your AndroidManifest.xml:

<uses-permission android:name="android.permission.READ_PHONE_STATE" />

in order to do this.

That being said, be careful about doing this. Not only will users wonder why your application is accessing their telephony stack, it might be difficult to migrate data over if the user gets a new device.

Update: As mentioned in the comments below, this is not a secure way to authenticate users, and raises privacy concerns. It is not recommended. Instead, look at the Google+ Login API if you want to implement a frictionless login system.

The Android Backup API is also available if you just want a lightweight way to persist a bundle of strings for when a user resets their phone (or buys a new device).

In addition to the answer of Trevor Johns, you can use this as follows:

TelephonyManager telephonyManager = (TelephonyManager)getSystemService(Context.TELEPHONY_SERVICE);
telephonyManager.getDeviceId();

And you should add the following permission into your Manifest.xml file:

<uses-permission android:name="android.permission.READ_PHONE_STATE"/>

In emulator, you'll probably get a like a "00000..." value. getDeviceId() returns NULL if device ID is not available.

I use the following code to get the IMEI or use Secure.ANDROID_ID as an alternative, when the device doesn't have phone capabilities:

/**
 * Returns the unique identifier for the device
 *
 * @return unique identifier for the device
 */
public String getDeviceIMEI() {
	String deviceUniqueIdentifier = null;
	TelephonyManager tm = (TelephonyManager) this.getSystemService(Context.TELEPHONY_SERVICE);
	if (null != tm) {
		deviceUniqueIdentifier = tm.getDeviceId();
	}
	if (null == deviceUniqueIdentifier || 0 == deviceUniqueIdentifier.length()) {
		deviceUniqueIdentifier = Settings.Secure.getString(this.getContentResolver(), Settings.Secure.ANDROID_ID);
	}
	return deviceUniqueIdentifier;
}

Or you can use the ANDROID_ID setting from Android.Provider.Settings.System (as described here strazerre.com).

This has the advantage that it doesn't require special permissions but can change if another application has write access and changes it (which is apparently unusual but not impossible).

Just for reference here is the code from the blog:

import android.provider.Settings;
import android.provider.Settings.System;   

String androidID = System.getString(this.getContentResolver(),Secure.ANDROID_ID);

Implementation note: if the ID is critical to the system architecture you need to be aware that in practice some of the very low end Android phones & tablets have been found reusing the same ANDROID_ID (9774d56d682e549c was the value showing up in our logs)

From: http://mytechead.wordpress.com/2011/08/28/how-to-get-imei-number-of-android-device/:

The following code helps in obtaining IMEI number of android devices :

TelephonyManager tm = (TelephonyManager)getSystemService(Context.TELEPHONY_SERVICE);
String device_id = tm.getDeviceId();

Permissions required in Android Manifest:

android.permission.READ_PHONE_STATE

NOTE: In case of tablets or devices which can’t act as Mobile Phone IMEI will be null.

to get IMEI (international mobile equipment identifier)

public String getIMEI(Activity activity) {
	TelephonyManager telephonyManager = (TelephonyManager) activity
			.getSystemService(Context.TELEPHONY_SERVICE);
	return telephonyManager.getDeviceId();
}

to get device unique id

public String getDeviceUniqueID(Activity activity){
	String device_unique_id = Secure.getString(activity.getContentResolver(),
		    Secure.ANDROID_ID);
	return device_unique_id;
}

For Android 6.0+ the game has changed so i suggest you use this;

The best way to go is during runtime else you get permission errors.

   /**
 * A loading screen after AppIntroActivity.
 */
public class LoadingActivity extends BaseActivity {
private static final int MY_PERMISSIONS_REQUEST_READ_PHONE_STATE = 0;
private TextView loading_tv2;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_loading);

    //trigger 'loadIMEI'
    loadIMEI();
    /** Fading Transition Effect */
    overridePendingTransition(android.R.anim.fade_in, android.R.anim.fade_out);
}

/**
 * Called when the 'loadIMEI' function is triggered.
 */
public void loadIMEI() {
    // Check if the READ_PHONE_STATE permission is already available.
    if (ActivityCompat.checkSelfPermission(this, Manifest.permission.READ_PHONE_STATE)
            != PackageManager.PERMISSION_GRANTED) {
        // READ_PHONE_STATE permission has not been granted.
        requestReadPhoneStatePermission();
    } else {
        // READ_PHONE_STATE permission is already been granted.
        doPermissionGrantedStuffs();
    }
}



/**
 * Requests the READ_PHONE_STATE permission.
 * If the permission has been denied previously, a dialog will prompt the user to grant the
 * permission, otherwise it is requested directly.
 */
private void requestReadPhoneStatePermission() {
    if (ActivityCompat.shouldShowRequestPermissionRationale(this,
            Manifest.permission.READ_PHONE_STATE)) {
        // Provide an additional rationale to the user if the permission was not granted
        // and the user would benefit from additional context for the use of the permission.
        // For example if the user has previously denied the permission.
        new AlertDialog.Builder(LoadingActivity.this)
                .setTitle("Permission Request")
                .setMessage(getString(R.string.permission_read_phone_state_rationale))
                .setCancelable(false)
                .setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int which) {
                        //re-request
                        ActivityCompat.requestPermissions(LoadingActivity.this,
                                new String[]{Manifest.permission.READ_PHONE_STATE},
                                MY_PERMISSIONS_REQUEST_READ_PHONE_STATE);
                    }
                })
                .setIcon(R.drawable.onlinlinew_warning_sign)
                .show();
    } else {
        // READ_PHONE_STATE permission has not been granted yet. Request it directly.
        ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.READ_PHONE_STATE},
                MY_PERMISSIONS_REQUEST_READ_PHONE_STATE);
    }
}

/**
 * Callback received when a permissions request has been completed.
 */
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions,
                                       @NonNull int[] grantResults) {

    if (requestCode == MY_PERMISSIONS_REQUEST_READ_PHONE_STATE) {
        // Received permission result for READ_PHONE_STATE permission.est.");
        // Check if the only required permission has been granted
        if (grantResults.length == 1 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
            // READ_PHONE_STATE permission has been granted, proceed with displaying IMEI Number
            //alertAlert(getString(R.string.permision_available_read_phone_state));
            doPermissionGrantedStuffs();
        } else {
            alertAlert(getString(R.string.permissions_not_granted_read_phone_state));
          }
    }
}

private void alertAlert(String msg) {
    new AlertDialog.Builder(LoadingActivity.this)
            .setTitle("Permission Request")
            .setMessage(msg)
            .setCancelable(false)
            .setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int which) {
                    // do somthing here
                }
            })
            .setIcon(R.drawable.onlinlinew_warning_sign)
            .show();
}


public void doPermissionGrantedStuffs() {
    //Have an  object of TelephonyManager
    TelephonyManager tm =(TelephonyManager)getSystemService(Context.TELEPHONY_SERVICE);
    //Get IMEI Number of Phone  //////////////// for this example i only need the IMEI
    String IMEINumber=tm.getDeviceId();

    /************************************************
     * **********************************************
     * This is just an icing on the cake
     * the following are other children of TELEPHONY_SERVICE
     *
     //Get Subscriber ID
     String subscriberID=tm.getDeviceId();

     //Get SIM Serial Number
     String SIMSerialNumber=tm.getSimSerialNumber();

     //Get Network Country ISO Code
     String networkCountryISO=tm.getNetworkCountryIso();

     //Get SIM Country ISO Code
     String SIMCountryISO=tm.getSimCountryIso();

     //Get the device software version
     String softwareVersion=tm.getDeviceSoftwareVersion()

     //Get the Voice mail number
     String voiceMailNumber=tm.getVoiceMailNumber();


     //Get the Phone Type CDMA/GSM/NONE
     int phoneType=tm.getPhoneType();

     switch (phoneType)
     {
     case (TelephonyManager.PHONE_TYPE_CDMA):
     // your code
     break;
     case (TelephonyManager.PHONE_TYPE_GSM)
     // your code
     break;
     case (TelephonyManager.PHONE_TYPE_NONE):
     // your code
     break;
     }

     //Find whether the Phone is in Roaming, returns true if in roaming
     boolean isRoaming=tm.isNetworkRoaming();
     if(isRoaming)
     phoneDetails+="\nIs In Roaming : "+"YES";
     else
     phoneDetails+="\nIs In Roaming : "+"NO";


     //Get the SIM state
     int SIMState=tm.getSimState();
     switch(SIMState)
     {
     case TelephonyManager.SIM_STATE_ABSENT :
     // your code
     break;
     case TelephonyManager.SIM_STATE_NETWORK_LOCKED :
     // your code
     break;
     case TelephonyManager.SIM_STATE_PIN_REQUIRED :
     // your code
     break;
     case TelephonyManager.SIM_STATE_PUK_REQUIRED :
     // your code
     break;
     case TelephonyManager.SIM_STATE_READY :
     // your code
     break;
     case TelephonyManager.SIM_STATE_UNKNOWN :
     // your code
     break;

     }
     */
    // Now read the desired content to a textview.
    loading_tv2 = (TextView) findViewById(R.id.loading_tv2);
    loading_tv2.setText(IMEINumber);
}
}

Hope this helps you or someone.

As in API 26 getDeviceId() is depreciated so you can use following code to cater API 26 and earlier versions

TelephonyManager telephonyManager = (TelephonyManager)getSystemService(Context.TELEPHONY_SERVICE);
String imei="";
if (android.os.Build.VERSION.SDK_INT >= 26) {
  imei=telephonyManager.getImei();
}
else
{
  imei=telephonyManager.getDeviceId();
}

Don't forget to add permission requests for READ_PHONE_STATE to use the above code.

UPDATE: From Android 10 its is restricted for user apps to get non-resettable hardware identifiers like IMEI.

New Update:

For Android Version 6 And Above, WLAN MAC Address has been deprecated , follow Trevor Johns answer

Update:

For uniquely Identification of devices, You can Use Secure.ANDROID_ID.

Old Answer:

Disadvantages of using IMEI as Unique Device ID:

• IMEI is dependent on the Simcard slot of the device, so it is not possible to get the IMEI for the devices that do not use Simcard. In Dual sim devices, we get 2 different IMEIs for the same device as it has 2 slots for simcard.

You can Use The WLAN MAC Address string (Not Recommended For Marshmallow and Marshmallow+ as WLAN MAC Address has been deprecated on Marshmallow forward. So you'll get a bogus value)

We can get the Unique ID for android phones using the WLAN MAC address also. The MAC address is unique for all devices and it works for all kinds of devices.

Advantages of using WLAN MAC address as Device ID:

• It is unique identifier for all type of devices (smart phones and tablets).

• It remains unique if the application is reinstalled

Disadvantages of using WLAN MAC address as Device ID:

• Give You a Bogus Value from Marshmallow and above.

• If device doesn’t have wifi hardware then you get null MAC address, but generally it is seen that most of the Android devices have wifi hardware and there are hardly few devices in the market with no wifi hardware.

SOURCE : technetexperts.com

The method getDeviceId() of TelephonyManager returns the unique device ID, for example, the IMEI for GSM and the MEID or ESN for CDMA phones. Return null if device ID is not available.

Java Code

package com.AndroidTelephonyManager;
  
import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.telephony.TelephonyManager;
import android.widget.TextView;
  
public class AndroidTelephonyManager extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    TextView textDeviceID = (TextView)findViewById(R.id.deviceid);
  
    //retrieve a reference to an instance of TelephonyManager
    TelephonyManager telephonyManager = (TelephonyManager)getSystemService(Context.TELEPHONY_SERVICE);
  
    textDeviceID.setText(getDeviceID(telephonyManager));
  
}
  
String getDeviceID(TelephonyManager phonyManager){
  
 String id = phonyManager.getDeviceId();
 if (id == null){
  id = "not available";
 }
  
 int phoneType = phonyManager.getPhoneType();
 switch(phoneType){
 case TelephonyManager.PHONE_TYPE_NONE:
  return "NONE: " + id;
  
 case TelephonyManager.PHONE_TYPE_GSM:
  return "GSM: IMEI=" + id;
  
 case TelephonyManager.PHONE_TYPE_CDMA:
  return "CDMA: MEID/ESN=" + id;
  
 /*
  *  for API Level 11 or above
  *  case TelephonyManager.PHONE_TYPE_SIP:
  *   return "SIP";
  */
  
 default:
  return "UNKNOWN: ID=" + id;
 }
  
}
}

XML

<linearlayout android:layout_height="fill_parent" android:layout_width="fill_parent" android:orientation="vertical" xmlns:android="http://schemas.android.com/apk/res/android">
<textview android:layout_height="wrap_content" android:layout_width="fill_parent" android:text="@string/hello">
<textview android:id="@+id/deviceid" android:layout_height="wrap_content" android:layout_width="fill_parent">
</textview></textview></linearlayout> 

Permission Required READ_PHONE_STATE in manifest file.

You can use this TelephonyManager TELEPHONY_SERVICE function to get unique device ID, Requires Permission: READ_PHONE_STATE

<uses-permission android:name="android.permission.READ_PHONE_STATE" />

Example, the IMEI for GSM and the MEID or ESN for CDMA phones.

/**
 * Gets the device unique id called IMEI. Sometimes, this returns 00000000000000000 for the
 * rooted devices.
 **/
public static String getDeviceImei(Context ctx) {
    TelephonyManager telephonyManager = (TelephonyManager) ctx.getSystemService(Context.TELEPHONY_SERVICE);
    return telephonyManager.getDeviceId();
}

Return null if device ID is not available.

Try this(need to get first IMEI always)

TelephonyManager mTelephony = (TelephonyManager) getSystemService(Context.TELEPHONY_SERVICE);
        if (ActivityCompat.checkSelfPermission(LoginActivity.this,Manifest.permission.READ_PHONE_STATE)!= PackageManager.PERMISSION_GRANTED) {

         return;
}

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
                if (mTelephony.getPhoneCount() == 2) {
                    IME = mTelephony.getImei(0);
                }else{
                    IME = mTelephony.getImei();
                }
            }else{
                if (mTelephony.getPhoneCount() == 2) {
                    IME = mTelephony.getDeviceId(0);
                } else {
                    IME = mTelephony.getDeviceId();
                }
            }
        } else {
            IME = mTelephony.getDeviceId();
        }

Use below code gives you IMEI number:

TelephonyManager telephonyManager = (TelephonyManager) getSystemService(Context.TELEPHONY_SERVICE);
System.out.println("IMEI::" + telephonyManager.getDeviceId());

The method getDeviceId() is deprecated. There a new method for this getImei(int)

Check here

You'll need the following permission in your AndroidManifest.xml:

<uses-permission android:name="android.permission.READ_PHONE_STATE" />

To get IMEI (international mobile equipment identifier) and if It is above API level 26 then we get telephonyManager.getImei() as null so for that, we use ANDROID_ID as a Unique Identifier.

 public static String getIMEINumber(@NonNull final Context context)
            throws SecurityException, NullPointerException {
        TelephonyManager tm = (TelephonyManager) context.getSystemService(Context.TELEPHONY_SERVICE);
        String imei;
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            assert tm != null;
            imei = tm.getImei();
            //this change is for Android 10 as per security concern it will not provide the imei number.
            if (imei == null) {
                imei = Settings.Secure.getString(context.getContentResolver(), Settings.Secure.ANDROID_ID);
            }
        } else {
            assert tm != null;
            if (tm.getDeviceId() != null && !tm.getDeviceId().equals("000000000000000")) {
                imei = tm.getDeviceId();
            } else {
                imei = Settings.Secure.getString(context.getContentResolver(), Settings.Secure.ANDROID_ID);
            }
        }

        return imei;
    }

for API Level 11 or above:

case TelephonyManager.PHONE_TYPE_SIP: 
return "SIP";

TelephonyManager tm= (TelephonyManager)getSystemService(Context.TELEPHONY_SERVICE);
textDeviceID.setText(getDeviceID(tm));

Kotlin Code for getting DeviceId ( IMEI ) with handling permission & comparability check for all android versions :

 val  telephonyManager = getSystemService(Context.TELEPHONY_SERVICE) as TelephonyManager
    if (ContextCompat.checkSelfPermission(this, Manifest.permission.READ_PHONE_STATE)
        == PackageManager.PERMISSION_GRANTED) {
        // Permission is  granted
        val imei : String? = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O)  telephonyManager.imei
        // older OS  versions
        else  telephonyManager.deviceId

        imei?.let {
            Log.i("Log", "DeviceId=$it" )
        }

    } else {  // Permission is not granted

    }

Also add this permission to AndroidManifest.xml :

<uses-permission android:name="android.permission.READ_PHONE_STATE"/> <!-- IMEI-->

use below code:

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
        String[] permissions = {Manifest.permission.READ_PHONE_STATE};
        if (ActivityCompat.checkSelfPermission(this,
                Manifest.permission.READ_PHONE_STATE) != PackageManager.PERMISSION_GRANTED) {
            requestPermissions(permissions, READ_PHONE_STATE);
        }
    } else {
        try {
            TelephonyManager telephonyManager = (TelephonyManager) getSystemService(Context.TELEPHONY_SERVICE);
            if (ActivityCompat.checkSelfPermission(this, Manifest.permission.READ_PHONE_STATE) != PackageManager.PERMISSION_GRANTED) {
                return;
            }
            String imei = telephonyManager.getDeviceId();

        } catch (Exception e) {
            e.printStackTrace();
        }
    }

And call onRequestPermissionsResult method following code:

@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
    switch (requestCode) {
        case READ_PHONE_STATE:
            if (grantResults.length > 0
                    && grantResults[0] == PackageManager.PERMISSION_GRANTED)
                try {
                    TelephonyManager telephonyManager = (TelephonyManager) getSystemService(Context.TELEPHONY_SERVICE);
                    if (ActivityCompat.checkSelfPermission(this, Manifest.permission.READ_PHONE_STATE) != PackageManager.PERMISSION_GRANTED) {
                        return;
                    }
                    String imei = telephonyManager.getDeviceId();

                } catch (Exception e) {
                    e.printStackTrace();
                }
    }
}

Add following permission in your AndroidManifest.xml:

<uses-permission android:name="android.permission.READ_PHONE_STATE" />

For Android 10 Following code is working for me.

val uid: String = Settings.Secure.getString(ctx.applicationContext.contentResolver, Settings.Secure.ANDROID_ID)
if (ContextCompat.checkSelfPermission(ctx, Manifest.permission.READ_PHONE_STATE) == PackageManager.PERMISSION_GRANTED) {
            imei = when {
                Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q -> {
                    uid
                }
                Build.VERSION.SDK_INT >= Build.VERSION_CODES.O -> {
                    telephonyManager.imei
                }
                else -> {
                    telephonyManager.deviceId
                }
            }
        }

For those looking for a Kotlin version, you can use something like this;

private fun telephonyService() {
    val telephonyManager = getSystemService(TELEPHONY_SERVICE) as TelephonyManager
    val imei = if (android.os.Build.VERSION.SDK_INT >= 26) {
        Timber.i("Phone >= 26 IMEI")
        telephonyManager.imei
    } else {
        Timber.i("Phone IMEI < 26")
        telephonyManager.deviceId
    }

    Timber.i("Phone IMEI $imei")
}

NOTE: You must wrap telephonyService() above with a permission check using checkSelfPermission or whatever method you use.

Also add this permission in the manifest file;

<uses-permission android:name="android.permission.READ_PHONE_STATE"/>

There is no Way you can get imei number from andorid 10+ or 29+ mobiles here is the alternative function that will be used for creating imei number for devices.

public  static String getDeviceID(){
    String devIDShort = "35" + //we make this look like a valid IMEI
            Build.BOARD.length()%10+ Build.BRAND.length()%10 +
            Build.CPU_ABI.length()%10 + Build.DEVICE.length()%10 +
            Build.DISPLAY.length()%10 + Build.HOST.length()%10 +
            Build.ID.length()%10 + Build.MANUFACTURER.length()%10 +
            Build.MODEL.length()%10 + Build.PRODUCT.length()%10 +
            Build.TAGS.length()%10 + Build.TYPE.length()%10 +
            Build.USER.length()%10 ; //13 digits

    return  devIDShort;
}

Restriction on non-resettable device identifiers

Starting in Android 10, apps must have the READ_PRIVILEGED_PHONE_STATE privileged permission in order to access the device's non-resettable identifiers, which include both IMEI and serial number.