diff --git a/keyserver/src/responders/user-responders.js b/keyserver/src/responders/user-responders.js
--- a/keyserver/src/responders/user-responders.js
+++ b/keyserver/src/responders/user-responders.js
@@ -78,6 +78,7 @@
   createAccount,
   processSIWEAccountCreation,
 } from '../creators/account-creator.js';
+import { createOlmSession } from '../creators/olm-session-creator.js';
 import { dbQuery, SQL } from '../database/database.js';
 import { deleteAccount } from '../deleters/account-deleters.js';
 import { deleteCookie } from '../deleters/cookie-deleters.js';
@@ -252,6 +253,7 @@
   +calendarQuery: ?CalendarQuery,
   +socialProof?: ?SIWESocialProof,
   +signedIdentityKeysBlob?: ?SignedIdentityKeysBlob,
+  +initialNotificationsEncryptedMessage?: string,
 };
 
 async function processSuccessfulLogin(
@@ -264,6 +266,7 @@
     calendarQuery,
     socialProof,
     signedIdentityKeysBlob,
+    initialNotificationsEncryptedMessage,
   } = params;
 
   const request: LogInRequest = input;
@@ -282,6 +285,17 @@
     deleteCookie(viewer.cookieID),
   ]);
   viewer.setNewCookie(userViewerData);
+  if (
+    userViewerData.cookieID &&
+    initialNotificationsEncryptedMessage &&
+    signedIdentityKeysBlob
+  ) {
+    await createOlmSession(
+      initialNotificationsEncryptedMessage,
+      'notifications',
+      userViewerData.cookieID,
+    );
+  }
 
   if (
     notAcknowledgedPolicies.length &&
@@ -361,6 +375,7 @@
   // old clients, but we no longer do anything with it.
   primaryIdentityPublicKey: t.maybe(tRegex(primaryIdentityPublicKeyRegex)),
   signedIdentityKeysBlob: t.maybe(signedIdentityKeysBlobValidator),
+  initialNotificationsEncryptedMessage: t.maybe(t.String),
 });
 
 async function logInResponder(
@@ -371,7 +386,8 @@
   const request: LogInRequest = input;
 
   let identityKeys: ?IdentityKeysBlob;
-  const { signedIdentityKeysBlob } = request;
+  const { signedIdentityKeysBlob, initialNotificationsEncryptedMessage } =
+    request;
   if (signedIdentityKeysBlob) {
     identityKeys = JSON.parse(signedIdentityKeysBlob.payload);
 
@@ -435,6 +451,7 @@
     userID: id,
     calendarQuery,
     signedIdentityKeysBlob,
+    initialNotificationsEncryptedMessage,
   });
 }
 
diff --git a/lib/types/account-types.js b/lib/types/account-types.js
--- a/lib/types/account-types.js
+++ b/lib/types/account-types.js
@@ -104,6 +104,7 @@
   +calendarQuery: CalendarQuery,
   +deviceTokenUpdateRequest?: ?DeviceTokenUpdateRequest,
   +signedIdentityKeysBlob?: SignedIdentityKeysBlob,
+  +initialNotificationsEncryptedMessage?: string,
 };
 
 export type LogInInfo = {
@@ -123,6 +124,7 @@
   +watchedIDs: $ReadOnlyArray<string>,
   +source?: LogInActionSource,
   +signedIdentityKeysBlob?: SignedIdentityKeysBlob,
+  +initialNotificationsEncryptedMessage?: string,
 };
 
 export type LogInResponse = {
diff --git a/native/account/log-in-panel.react.js b/native/account/log-in-panel.react.js
--- a/native/account/log-in-panel.react.js
+++ b/native/account/log-in-panel.react.js
@@ -37,6 +37,7 @@
 import { useSelector } from '../redux/redux-utils.js';
 import { nativeLogInExtraInfoSelector } from '../selectors/account-selectors.js';
 import type { KeyPressEvent } from '../types/react-native.js';
+import { useInitialNotificationsEncryptedMessage } from '../utils/crypto-utils.js';
 import type { StateContainer } from '../utils/state-container.js';
 
 export type LogInState = {
@@ -54,6 +55,9 @@
   +logInExtraInfo: () => Promise<LogInExtraInfo>,
   +dispatchActionPromise: DispatchActionPromise,
   +logIn: (logInInfo: LogInInfo) => Promise<LogInResult>,
+  +initialNotificationsEncryptedMessage: (
+    oneTimeKeysCount: number,
+  ) => Promise<string>,
 };
 class LogInPanel extends React.PureComponent<Props> {
   usernameInput: ?TextInput;
@@ -227,9 +231,12 @@
 
     Keyboard.dismiss();
     const extraInfo = await this.props.logInExtraInfo();
+    const initialNotificationsEncryptedMessage =
+      await this.props.initialNotificationsEncryptedMessage(1);
+    console.log(initialNotificationsEncryptedMessage);
     this.props.dispatchActionPromise(
       logInActionTypes,
-      this.logInAction(extraInfo),
+      this.logInAction({ ...extraInfo, initialNotificationsEncryptedMessage }),
       undefined,
       ({ calendarQuery: extraInfo.calendarQuery }: LogInStartingPayload),
     );
@@ -364,6 +371,8 @@
 
     const dispatchActionPromise = useDispatchActionPromise();
     const callLogIn = useServerCall(logIn);
+    const callInitialNotificationsEncryptedMessage =
+      useInitialNotificationsEncryptedMessage();
 
     return (
       <LogInPanel
@@ -372,6 +381,9 @@
         logInExtraInfo={logInExtraInfo}
         dispatchActionPromise={dispatchActionPromise}
         logIn={callLogIn}
+        initialNotificationsEncryptedMessage={
+          callInitialNotificationsEncryptedMessage
+        }
       />
     );
   });