diff --git a/src/components/structures/MatrixChat.js b/src/components/structures/MatrixChat.js
index a93492cd41..063276c309 100644
--- a/src/components/structures/MatrixChat.js
+++ b/src/components/structures/MatrixChat.js
@@ -283,29 +283,32 @@ export default React.createClass({
         }
 
         // the first thing to do is to try the token params in the query-string
-        Lifecycle.attemptTokenLogin(this.props.realQueryParams).then((loggedIn) => {
-            if (loggedIn) {
-                this.props.onTokenLoginCompleted();
+        // if the session isn't soft logged out (ie: is a clean session being logged in)
+        if (!Lifecycle.isSoftLogout()) {
+            Lifecycle.attemptTokenLogin(this.props.realQueryParams).then((loggedIn) => {
+                if (loggedIn) {
+                    this.props.onTokenLoginCompleted();
 
-                // don't do anything else until the page reloads - just stay in
-                // the 'loading' state.
-                return;
-            }
+                    // don't do anything else until the page reloads - just stay in
+                    // the 'loading' state.
+                    return;
+                }
 
-            // if the user has followed a login or register link, don't reanimate
-            // the old creds, but rather go straight to the relevant page
-            const firstScreen = this._screenAfterLogin ?
-                this._screenAfterLogin.screen : null;
+                // if the user has followed a login or register link, don't reanimate
+                // the old creds, but rather go straight to the relevant page
+                const firstScreen = this._screenAfterLogin ?
+                    this._screenAfterLogin.screen : null;
 
-            if (firstScreen === 'login' ||
+                if (firstScreen === 'login' ||
                     firstScreen === 'register' ||
                     firstScreen === 'forgot_password') {
-                this._showScreenAfterLogin();
-                return;
-            }
+                    this._showScreenAfterLogin();
+                    return;
+                }
 
-            return this._loadSession();
-        });
+                return this._loadSession();
+            });
+        }
 
         if (SettingsStore.getValue("showCookieBar")) {
             this.setState({
@@ -1250,10 +1253,7 @@ export default React.createClass({
             this._screenAfterLogin = null;
         } else if (localStorage && localStorage.getItem('mx_last_room_id')) {
             // Before defaulting to directory, show the last viewed room
-            dis.dispatch({
-                action: 'view_room',
-                room_id: localStorage.getItem('mx_last_room_id'),
-            });
+            this._viewLastRoom();
         } else {
             if (MatrixClientPeg.get().isGuest()) {
                 dis.dispatch({action: 'view_welcome_page'});
@@ -1267,6 +1267,13 @@ export default React.createClass({
         }
     },
 
+    _viewLastRoom: function() {
+        dis.dispatch({
+            action: 'view_room',
+            room_id: localStorage.getItem('mx_last_room_id'),
+        });
+    },
+
     /**
      * Called when the session is logged out
      */
@@ -1565,6 +1572,17 @@ export default React.createClass({
                 action: 'start_password_recovery',
                 params: params,
             });
+        } else if (screen === 'soft_logout') {
+            if (MatrixClientPeg.get() && MatrixClientPeg.get().getUserId()) {
+                // Logged in - visit a room
+                this._viewLastRoom();
+            } else {
+                // Ultimately triggers soft_logout if needed
+                dis.dispatch({
+                    action: 'start_login',
+                    params: params,
+                });
+            }
         } else if (screen == 'new') {
             dis.dispatch({
                 action: 'view_create_room',
@@ -1957,7 +1975,10 @@ export default React.createClass({
         if (this.state.view === VIEWS.SOFT_LOGOUT) {
             const SoftLogout = sdk.getComponent('structures.auth.SoftLogout');
             return (
-                <SoftLogout />
+                <SoftLogout
+                    realQueryParams={this.props.realQueryParams}
+                    onTokenLoginCompleted={this.props.onTokenLoginCompleted}
+                />
             );
         }
 
diff --git a/src/components/structures/auth/SoftLogout.js b/src/components/structures/auth/SoftLogout.js
index bd6a5912e2..9342c6086e 100644
--- a/src/components/structures/auth/SoftLogout.js
+++ b/src/components/structures/auth/SoftLogout.js
@@ -15,6 +15,7 @@ limitations under the License.
 */
 
 import React from 'react';
+import PropTypes from 'prop-types';
 import {_t} from '../../../languageHandler';
 import sdk from '../../../index';
 import dis from '../../../dispatcher';
@@ -24,6 +25,7 @@ import {ValidatedServerConfig} from "../../../utils/AutoDiscoveryUtils";
 import SdkConfig from "../../../SdkConfig";
 import MatrixClientPeg from "../../../MatrixClientPeg";
 import {sendLoginRequest} from "../../../Login";
+import url from 'url';
 
 const LOGIN_VIEW = {
     LOADING: 1,
@@ -41,7 +43,11 @@ const FLOWS_TO_VIEWS = {
 
 export default class SoftLogout extends React.Component {
     static propTypes = {
-        // Nothing.
+        // Query parameters from MatrixChat
+        realQueryParams: PropTypes.object, // {homeserver, identityServer, loginToken}
+
+        // Called when the SSO login completes
+        onTokenLoginCompleted: PropTypes.func,
     };
 
     constructor() {
@@ -67,6 +73,7 @@ export default class SoftLogout extends React.Component {
             displayName,
             loginView: LOGIN_VIEW.LOADING,
             keyBackupNeeded: true, // assume we do while we figure it out (see componentWillMount)
+            ssoUrl: null,
 
             busy: false,
             password: "",
@@ -75,6 +82,12 @@ export default class SoftLogout extends React.Component {
     }
 
     componentDidMount(): void {
+        // We've ended up here when we don't need to - navigate to login
+        if (!Lifecycle.isSoftLogout()) {
+            dis.dispatch({action: "on_logged_in"});
+            return;
+        }
+
         this._initLogin();
 
         MatrixClientPeg.get().flagAllGroupSessionsForBackup().then(remaining => {
@@ -95,6 +108,15 @@ export default class SoftLogout extends React.Component {
     };
 
     async _initLogin() {
+        const requiredQueryParams = ['homeserver', 'loginToken'];
+        const hasAllParams = requiredQueryParams
+            .filter(p => Object.keys(this.props.realQueryParams).includes(p)).length === requiredQueryParams.length;
+        if (this.props.realQueryParams && hasAllParams) {
+            this.setState({loginView: LOGIN_VIEW.LOADING});
+            this.trySsoLogin();
+            return;
+        }
+
         // Note: we don't use the existing Login class because it is heavily flow-based. We don't
         // care about login flows here, unless it is the single flow we support.
         const client = MatrixClientPeg.get();
@@ -102,6 +124,18 @@ export default class SoftLogout extends React.Component {
 
         const chosenView = loginViews.filter(f => !!f)[0] || LOGIN_VIEW.UNSUPPORTED;
         this.setState({loginView: chosenView});
+
+        if (chosenView === LOGIN_VIEW.CAS || chosenView === LOGIN_VIEW.SSO) {
+            const client = MatrixClientPeg.get();
+
+            const appUrl = url.parse(window.location.href, true);
+            appUrl.hash = ""; // Clear #/soft_logout off the URL
+            appUrl.query["homeserver"] = client.getHomeserverUrl();
+            appUrl.query["identityServer"] = client.getIdentityServerUrl();
+
+            const ssoUrl = client.getSsoLoginUrl(url.format(appUrl), chosenView === LOGIN_VIEW.CAS ? "cas" : "sso");
+            this.setState({ssoUrl});
+        }
     }
 
     onPasswordChange = (ev) => {
@@ -152,6 +186,42 @@ export default class SoftLogout extends React.Component {
         });
     };
 
+    async trySsoLogin() {
+        this.setState({busy: true});
+
+        const hsUrl = this.props.realQueryParams['homeserver'];
+        const isUrl = this.props.realQueryParams['identityServer'] || MatrixClientPeg.get().getIdentityServerUrl();
+        const loginType = "m.login.token";
+        const loginParams = {
+            token: this.props.realQueryParams['loginToken'],
+            device_id: MatrixClientPeg.get().getDeviceId(),
+        };
+
+        let credentials = null;
+        try {
+            credentials = await sendLoginRequest(hsUrl, isUrl, loginType, loginParams);
+        } catch (e) {
+            console.error(e);
+            this.setState({busy: false, loginView: LOGIN_VIEW.UNSUPPORTED});
+            return;
+        }
+
+        Lifecycle.hydrateSession(credentials).then(() => {
+            if (this.props.onTokenLoginCompleted) this.props.onTokenLoginCompleted();
+        }).catch((e) => {
+            console.error(e);
+            this.setState({busy: false, loginView: LOGIN_VIEW.UNSUPPORTED});
+        });
+    }
+
+    onSsoLogin = async (ev) => {
+        ev.preventDefault();
+        ev.stopPropagation();
+
+        this.setState({busy: true});
+        window.location.href = this.state.ssoUrl;
+    };
+
     _renderSignInSection() {
         if (this.state.loginView === LOGIN_VIEW.LOADING) {
             const Spinner = sdk.getComponent("elements.Spinner");
@@ -202,8 +272,12 @@ export default class SoftLogout extends React.Component {
         }
 
         if (this.state.loginView === LOGIN_VIEW.SSO || this.state.loginView === LOGIN_VIEW.CAS) {
-            // TODO: TravisR - https://github.com/vector-im/riot-web/issues/10238
-            return <p>PLACEHOLDER</p>;
+            const AccessibleButton = sdk.getComponent('elements.AccessibleButton');
+            return (
+                <AccessibleButton kind='primary' onClick={this.onSsoLogin}>
+                    {_t('Sign in with single sign-on')}
+                </AccessibleButton>
+            );
         }
 
         // Default: assume unsupported