diff --git a/js/profile-menu.js b/js/profile-menu.js
index ca252c1..d2650d0 100644
--- a/js/profile-menu.js
+++ b/js/profile-menu.js
@@ -155,6 +155,11 @@
     const action = t.dataset.action;
     if (action === "signout") {
       try { localStorage.removeItem("siriusProfile"); } catch {}
+      // Also drop the session-cached seed so a reload after sign-out really
+      // signs the user out (else the next page load would silently rebuild
+      // the same wallet from sessionStorage).
+      try { sessionStorage.removeItem("siriusSessionMnemonic"); sessionStorage.removeItem("siriusSessionSource"); } catch {}
+      try { delete window.siriusWallet; } catch { window.siriusWallet = null; }
       window.dispatchEvent(new Event("siriusProfileChanged"));
       // Reload so any signed-in section on the current page (portal, tld) resets.
       location.reload();
diff --git a/js/register-flow.js b/js/register-flow.js
index 702e8e7..9ed1e83 100644
--- a/js/register-flow.js
+++ b/js/register-flow.js
@@ -242,11 +242,20 @@ function writeProfile(w) {
 // mode, mark siriusProfile and close the modal here; otherwise return
 // false so the caller keeps going to Fund → Confirm → Register.
 function finishSignIn(w) {
-  writeProfile({ address: w.address, tokenAddress: w.tokenAddress, source: w.source ?? "seed" });
-  // Expose the live wallet globally so the portal / TLD page can pick it up
-  // without re-prompting for a password. In-memory only — cleared on reload,
-  // sign-out, or navigation away.
+  // Expose the live wallet globally BEFORE writeProfile so any listener of
+  // siriusProfileChanged (portal.html adoptWalletFromModal) sees the wallet
+  // and can switch to the signed-in view synchronously.
   window.siriusWallet = w;
+  // Session-cache the seed so a page reload restores the wallet without
+  // asking for the password again. sessionStorage is per-tab and clears on
+  // browser close — same lifetime as a "keep me signed in for this session"
+  // toggle in a normal app. Chipnet-only convenience; mainnet gets the PIN
+  // escrow pattern (see finishSignIn comment history).
+  try {
+    if (w?.mnemonic) sessionStorage.setItem("siriusSessionMnemonic", w.mnemonic);
+    if (w?.source === "wc") sessionStorage.setItem("siriusSessionSource", "wc");
+  } catch {}
+  writeProfile({ address: w.address, tokenAddress: w.tokenAddress, source: w.source ?? "seed" });
   if (state.signInOnly) {
     render(`<h3><span class="ok">✓</span> Signed in</h3>
       <p class="sub">You are signed in as <span class="mono">${esc(w.address)}</span>. Names you own
@@ -337,7 +346,24 @@ function adoptSignedInWallet() {
   return false;
 }
 
-function startFlow(name, opts = {}) {
+// Best-effort silent rebuild from sessionStorage — same session ⇒ same
+// wallet, no password prompt. Returns true when the wallet is ready.
+async function adoptSessionWalletAsync() {
+  if (state.wallet) return true;
+  if (adoptSignedInWallet()) return true;
+  try {
+    const cached = typeof sessionStorage !== "undefined"
+      ? sessionStorage.getItem("siriusSessionMnemonic")
+      : null;
+    if (!cached) return false;
+    const w = await BNS.BuiltInWallet.fromMnemonic(cached);
+    window.siriusWallet = w;
+    state.wallet = w;
+    return true;
+  } catch { return false; }
+}
+
+async function startFlow(name, opts = {}) {
   state.name = name;
   state.tld = null;
   state.signInOnly = false;
@@ -350,7 +376,7 @@ function startFlow(name, opts = {}) {
     ? BigInt(opts.serviceFeeSats)
     : (p ? p.sats : null);
   open();
-  if (adoptSignedInWallet()) stepFund();
+  if (await adoptSessionWalletAsync()) stepFund();
   else stepWallet();
 }
 
@@ -358,12 +384,12 @@ function startFlow(name, opts = {}) {
 // the mint step calls registerTldWith(Built|External)Wallet instead of the
 // name variant, and the "done" screen skips the record editor since a TLD
 // certificate goes to the operator's token address as-is.
-function startTldFlow(label, opts = {}) {
+async function startTldFlow(label, opts = {}) {
   state.name = `.${label}`;          // used for headings only
   state.tld = { label, serviceFeeSats: BigInt(opts.serviceFeeSats ?? 0n) };
   state.signInOnly = false;
   open();
-  if (adoptSignedInWallet()) stepFund();
+  if (await adoptSessionWalletAsync()) stepFund();
   else stepWallet();
 }
 
diff --git a/portal.html b/portal.html
index 71ca787..c69665f 100644
--- a/portal.html
+++ b/portal.html
@@ -278,6 +278,20 @@ async function adoptWalletFromModal() {
     await enterPortal();
     return true;
   }
+  // No live wallet in memory — but if a session mnemonic is cached from an
+  // earlier sign-in in this browser session, rebuild the wallet silently.
+  // Same tab (or a reload) keeps the user signed in; a full browser close
+  // clears sessionStorage and drops the user back to Unlock.
+  try {
+    const cached = sessionStorage.getItem("siriusSessionMnemonic");
+    if (cached) {
+      const w = await BNS.BuiltInWallet.fromMnemonic(cached);
+      wallet = w;
+      window.siriusWallet = w;
+      await enterPortal();
+      return true;
+    }
+  } catch { /* fall through to sign-in prompt */ }
   return false;
 }
 function readProfile() {