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
@@ -100,6 +100,7 @@
   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';
@@ -339,6 +340,7 @@
   +calendarQuery: ?CalendarQuery,
   +socialProof?: ?SIWESocialProof,
   +signedIdentityKeysBlob?: ?SignedIdentityKeysBlob,
+  +initialNotificationsEncryptedMessage?: string,
 };
 
 async function processSuccessfulLogin(
@@ -351,6 +353,7 @@
     calendarQuery,
     socialProof,
     signedIdentityKeysBlob,
+    initialNotificationsEncryptedMessage,
   } = params;
 
   const request: LogInRequest = input;
@@ -393,6 +396,19 @@
   if (calendarQuery) {
     await setNewSession(viewer, calendarQuery, newServerTime);
   }
+  const olmSessionPromise = (async () => {
+    if (
+      userViewerData.cookieID &&
+      initialNotificationsEncryptedMessage &&
+      signedIdentityKeysBlob
+    ) {
+      await createOlmSession(
+        initialNotificationsEncryptedMessage,
+        'notifications',
+        userViewerData.cookieID,
+      );
+    }
+  })();
 
   const threadCursors = {};
   for (const watchedThreadID of request.watchedIDs) {
@@ -412,6 +428,7 @@
     calendarQuery ? fetchEntryInfos(viewer, [calendarQuery]) : undefined,
     fetchKnownUserInfos(viewer),
     fetchLoggedInUserInfo(viewer),
+    olmSessionPromise,
   ]);
 
   const rawEntryInfos = entriesResult ? entriesResult.rawEntryInfos : null;
@@ -448,6 +465,7 @@
   // old clients, but we no longer do anything with it.
   primaryIdentityPublicKey: t.maybe(tRegex(primaryIdentityPublicKeyRegex)),
   signedIdentityKeysBlob: t.maybe(signedIdentityKeysBlobValidator),
+  initialNotificationsEncryptedMessage: t.maybe(t.String),
 });
 
 export const logInResponseValidator: TInterface<LogInResponse> =
@@ -479,7 +497,8 @@
   );
 
   let identityKeys: ?IdentityKeysBlob;
-  const { signedIdentityKeysBlob } = request;
+  const { signedIdentityKeysBlob, initialNotificationsEncryptedMessage } =
+    request;
   if (signedIdentityKeysBlob) {
     identityKeys = JSON.parse(signedIdentityKeysBlob.payload);
 
@@ -543,6 +562,7 @@
     userID: id,
     calendarQuery,
     signedIdentityKeysBlob,
+    initialNotificationsEncryptedMessage,
   });
   return validateOutput(
     viewer.platformDetails,
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
@@ -109,6 +109,7 @@
   +calendarQuery: CalendarQuery,
   +deviceTokenUpdateRequest?: ?DeviceTokenUpdateRequest,
   +signedIdentityKeysBlob?: SignedIdentityKeysBlob,
+  +initialNotificationsEncryptedMessage?: string,
 };
 
 export type LogInInfo = {
@@ -129,6 +130,7 @@
   +source?: LogInActionSource,
   +primaryIdentityPublicKey?: empty,
   +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 +55,7 @@
   +logInExtraInfo: () => Promise<LogInExtraInfo>,
   +dispatchActionPromise: DispatchActionPromise,
   +logIn: (logInInfo: LogInInfo) => Promise<LogInResult>,
+  +initialNotificationsEncryptedMessage: () => Promise<string>,
 };
 class LogInPanel extends React.PureComponent<Props> {
   usernameInput: ?TextInput;
@@ -227,9 +229,12 @@
 
     Keyboard.dismiss();
     const extraInfo = await this.props.logInExtraInfo();
+    const initialNotificationsEncryptedMessage =
+      await this.props.initialNotificationsEncryptedMessage();
+
     this.props.dispatchActionPromise(
       logInActionTypes,
-      this.logInAction(extraInfo),
+      this.logInAction({ ...extraInfo, initialNotificationsEncryptedMessage }),
       undefined,
       ({ calendarQuery: extraInfo.calendarQuery }: LogInStartingPayload),
     );
@@ -364,6 +369,8 @@
 
     const dispatchActionPromise = useDispatchActionPromise();
     const callLogIn = useServerCall(logIn);
+    const callInitialNotificationsEncryptedMessage =
+      useInitialNotificationsEncryptedMessage();
 
     return (
       <LogInPanel
@@ -372,6 +379,9 @@
         logInExtraInfo={logInExtraInfo}
         dispatchActionPromise={dispatchActionPromise}
         logIn={callLogIn}
+        initialNotificationsEncryptedMessage={
+          callInitialNotificationsEncryptedMessage
+        }
       />
     );
   });