diff --git a/CHANGES.md b/CHANGES.md
index ba3ad08037..a3eb4bfdf9 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -41,6 +41,7 @@ Improvements 🙌:
  - Improve room profile UX
  - Upgrade Jitsi library from 2.9.3 to 3.1.0
  - a11y improvements
+ - Pre-share session keys when opening a room or start typing (#2771)
 
 Bugfix 🐛:
  - VoIP : fix audio devices output
diff --git a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/MatrixConfiguration.kt b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/MatrixConfiguration.kt
index 93a1b962ed..c01aeab6dd 100644
--- a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/MatrixConfiguration.kt
+++ b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/MatrixConfiguration.kt
@@ -17,6 +17,7 @@
 package org.matrix.android.sdk.api
 
 import org.matrix.android.sdk.api.crypto.MXCryptoConfig
+import org.matrix.android.sdk.api.crypto.OutboundSessionKeySharingStrategy
 import java.net.Proxy
 
 data class MatrixConfiguration(
@@ -40,6 +41,7 @@ data class MatrixConfiguration(
          * True to advertise support for call transfers to other parties on Matrix calls.
          */
         val supportsCallTransfer: Boolean = false
+        val outboundSessionKeySharingStrategy: OutboundSessionKeySharingStrategy = OutboundSessionKeySharingStrategy.WhenSendingEvent
 ) {
 
     /**
diff --git a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/crypto/OutboundSessionKeySharingStrategy.kt b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/crypto/OutboundSessionKeySharingStrategy.kt
new file mode 100644
index 0000000000..9ef1f538b8
--- /dev/null
+++ b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/crypto/OutboundSessionKeySharingStrategy.kt
@@ -0,0 +1,34 @@
+/*
+ * Copyright 2020 The Matrix.org Foundation C.I.C.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.matrix.android.sdk.api.crypto
+
+enum class OutboundSessionKeySharingStrategy {
+    /**
+     * Keys will be sent for the first time when the first message is sent
+     */
+    WhenSendingEvent,
+
+    /**
+     * Keys will be sent for the first time when the timeline displayed
+     */
+    WhenEnteringRoom,
+
+    /**
+     * Keys will be sent for the first time when a typing started
+     */
+    WhenTyping
+}
diff --git a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/session/crypto/CryptoService.kt b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/session/crypto/CryptoService.kt
index eead9b4ab7..1c5bfb1a7b 100644
--- a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/session/crypto/CryptoService.kt
+++ b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/session/crypto/CryptoService.kt
@@ -156,4 +156,6 @@ interface CryptoService {
     fun getWithHeldMegolmSession(roomId: String, sessionId: String): RoomKeyWithHeldContent?
 
     fun logDbUsageInfo()
+
+    fun ensureOutboundSession(roomId: String)
 }
diff --git a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/crypto/DefaultCryptoService.kt b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/crypto/DefaultCryptoService.kt
index 67229a5eae..821ac18e3a 100755
--- a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/crypto/DefaultCryptoService.kt
+++ b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/crypto/DefaultCryptoService.kt
@@ -1290,6 +1290,21 @@ internal class DefaultCryptoService @Inject constructor(
         cryptoStore.logDbUsageInfo()
     }
 
+    override fun ensureOutboundSession(roomId: String) {
+        cryptoCoroutineScope.launch(coroutineDispatchers.crypto) {
+            roomEncryptorsStore
+                    .get(roomId)
+                    ?.let {
+                        getEncryptionAlgorithm(roomId)?.let { safeAlgorithm ->
+                            val userIds = getRoomUserIds(roomId)
+                            if (setEncryptionInRoom(roomId, safeAlgorithm, false, userIds)) {
+                                roomEncryptorsStore.get(roomId)?.ensureOutboundSession(getRoomUserIds(roomId))
+                            }
+                        }
+                    }
+        }
+    }
+
     /* ==========================================================================================
      * For test only
      * ========================================================================================== */
diff --git a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/crypto/algorithms/IMXEncrypting.kt b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/crypto/algorithms/IMXEncrypting.kt
index fc3ea08a21..008ef1b084 100644
--- a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/crypto/algorithms/IMXEncrypting.kt
+++ b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/crypto/algorithms/IMXEncrypting.kt
@@ -62,4 +62,11 @@ internal interface IMXEncrypting {
                            userId: String,
                            deviceId: String,
                            senderKey: String): Boolean
+
+    /**
+     * Ensure the outbound session
+     *
+     * @param usersInRoom the users in the room
+     */
+    suspend fun ensureOutboundSession(usersInRoom: List<String>)
 }
diff --git a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/crypto/algorithms/megolm/MXMegolmEncryption.kt b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/crypto/algorithms/megolm/MXMegolmEncryption.kt
index fa8acafb83..3a07dbcfb6 100644
--- a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/crypto/algorithms/megolm/MXMegolmEncryption.kt
+++ b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/crypto/algorithms/megolm/MXMegolmEncryption.kt
@@ -137,11 +137,10 @@ internal class MXMegolmEncryption(
         return MXOutboundSessionInfo(sessionId, SharedWithHelper(roomId, sessionId, cryptoStore))
     }
 
-    /**
-     * Ensure the outbound session
-     *
-     * @param devicesInRoom the devices list
-     */
+    override suspend fun ensureOutboundSession(usersInRoom: List<String>) {
+        getDevicesInRoom(usersInRoom).allowedDevices
+    }
+
     private suspend fun ensureOutboundSession(devicesInRoom: MXUsersDevicesMap<CryptoDeviceInfo>): MXOutboundSessionInfo {
         Timber.v("## CRYPTO | ensureOutboundSession start")
         var session = outboundSession
diff --git a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/crypto/algorithms/olm/MXOlmEncryption.kt b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/crypto/algorithms/olm/MXOlmEncryption.kt
index 9acc9bc1b2..acea6ff3fe 100644
--- a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/crypto/algorithms/olm/MXOlmEncryption.kt
+++ b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/crypto/algorithms/olm/MXOlmEncryption.kt
@@ -85,4 +85,8 @@ internal class MXOlmEncryption(
         // No need for olm
         return false
     }
+
+    override suspend fun ensureOutboundSession(usersInRoom: List<String>) {
+        // NOOP
+    }
 }
diff --git a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/session/room/timeline/DefaultTimeline.kt b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/session/room/timeline/DefaultTimeline.kt
index ca272a3520..e75beb4b21 100644
--- a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/session/room/timeline/DefaultTimeline.kt
+++ b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/session/room/timeline/DefaultTimeline.kt
@@ -24,9 +24,13 @@ import io.realm.RealmQuery
 import io.realm.RealmResults
 import io.realm.Sort
 import org.matrix.android.sdk.api.MatrixCallback
+import org.matrix.android.sdk.api.MatrixConfiguration
 import org.matrix.android.sdk.api.NoOpMatrixCallback
+import org.matrix.android.sdk.api.crypto.OutboundSessionKeySharingStrategy
 import org.matrix.android.sdk.api.extensions.orFalse
 import org.matrix.android.sdk.api.extensions.tryOrNull
+import org.matrix.android.sdk.api.session.Session
+import org.matrix.android.sdk.api.session.crypto.CryptoService
 import org.matrix.android.sdk.api.session.events.model.EventType
 import org.matrix.android.sdk.api.session.events.model.RelationType
 import org.matrix.android.sdk.api.session.events.model.toModel
@@ -80,8 +84,11 @@ internal class DefaultTimeline(
         private val timelineInput: TimelineInput,
         private val eventDecryptor: TimelineEventDecryptor,
         private val realmSessionProvider: RealmSessionProvider,
-        private val loadRoomMembersTask: LoadRoomMembersTask
-) : Timeline,
+        private val loadRoomMembersTask: LoadRoomMembersTask,
+        private val session: Session,
+        private val matrixConfiguration: MatrixConfiguration,
+        private val cryptoService: CryptoService
+        ) : Timeline,
         TimelineHiddenReadReceipts.Delegate,
         TimelineInput.Listener {
 
@@ -188,6 +195,11 @@ internal class DefaultTimeline(
                         }
                         .executeBy(taskExecutor)
 
+                if (session.getRoom(roomId)?.isEncrypted().orFalse()
+                        && matrixConfiguration.outboundSessionKeySharingStrategy == OutboundSessionKeySharingStrategy.WhenEnteringRoom) {
+                    cryptoService.ensureOutboundSession(roomId)
+                }
+
                 isReady.set(true)
             }
         }
diff --git a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/session/room/typing/SendTypingTask.kt b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/session/room/typing/SendTypingTask.kt
index 3b56d04872..aa8dcf6013 100644
--- a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/session/room/typing/SendTypingTask.kt
+++ b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/session/room/typing/SendTypingTask.kt
@@ -21,6 +21,11 @@ import org.matrix.android.sdk.internal.network.executeRequest
 import org.matrix.android.sdk.internal.session.room.RoomAPI
 import org.matrix.android.sdk.internal.task.Task
 import kotlinx.coroutines.delay
+import org.matrix.android.sdk.api.MatrixConfiguration
+import org.matrix.android.sdk.api.crypto.OutboundSessionKeySharingStrategy
+import org.matrix.android.sdk.api.extensions.orFalse
+import org.matrix.android.sdk.api.session.Session
+import org.matrix.android.sdk.api.session.crypto.CryptoService
 import org.matrix.android.sdk.internal.network.GlobalErrorReceiver
 import javax.inject.Inject
 
@@ -38,12 +43,21 @@ internal interface SendTypingTask : Task<SendTypingTask.Params, Unit> {
 internal class DefaultSendTypingTask @Inject constructor(
         private val roomAPI: RoomAPI,
         @UserId private val userId: String,
-        private val globalErrorReceiver: GlobalErrorReceiver
+        private val globalErrorReceiver: GlobalErrorReceiver,
+        private val matrixConfiguration: MatrixConfiguration,
+        private val session: Session,
+        private val cryptoService: CryptoService
 ) : SendTypingTask {
 
     override suspend fun execute(params: SendTypingTask.Params) {
         delay(params.delay ?: -1)
 
+        if (params.isTyping
+                && session.getRoom(params.roomId)?.isEncrypted().orFalse()
+                && matrixConfiguration.outboundSessionKeySharingStrategy == OutboundSessionKeySharingStrategy.WhenTyping) {
+            cryptoService.ensureOutboundSession(params.roomId)
+        }
+
         executeRequest<Unit>(globalErrorReceiver) {
             apiCall = roomAPI.sendTypingState(
                     params.roomId,
diff --git a/vector/build.gradle b/vector/build.gradle
index 5543d27d95..a257f6aaf6 100644
--- a/vector/build.gradle
+++ b/vector/build.gradle
@@ -136,6 +136,8 @@ android {
         buildConfigField "String", "BUILD_NUMBER", "\"${buildNumber}\""
         resValue "string", "build_number", "\"${buildNumber}\""
 
+        buildConfigField "org.matrix.android.sdk.api.crypto.OutboundSessionKeySharingStrategy", "OutboundSessionKeySharingStrategy", "org.matrix.android.sdk.api.crypto.OutboundSessionKeySharingStrategy.WhenTyping"
+
         testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
 
         // Keep abiFilter for the universalApk
diff --git a/vector/src/main/java/im/vector/app/VectorApplication.kt b/vector/src/main/java/im/vector/app/VectorApplication.kt
index f8cda2c417..1926a35c9c 100644
--- a/vector/src/main/java/im/vector/app/VectorApplication.kt
+++ b/vector/src/main/java/im/vector/app/VectorApplication.kt
@@ -205,7 +205,7 @@ class VectorApplication :
         }
     }
 
-    override fun providesMatrixConfiguration() = MatrixConfiguration(BuildConfig.FLAVOR_DESCRIPTION)
+    override fun providesMatrixConfiguration() = MatrixConfiguration(applicationFlavor = BuildConfig.FLAVOR_DESCRIPTION, outboundSessionKeySharingStrategy = BuildConfig.OutboundSessionKeySharingStrategy)
 
     override fun getWorkManagerConfiguration(): WorkConfiguration {
         return WorkConfiguration.Builder()