diff --git a/CHANGELOG.md b/CHANGELOG.md
index ff8f767..286655a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,7 +10,7 @@ and this project follows [Semantic Versioning](https://semver.org/).
 ### Fixed
 
 - Self-service kiosk: closed events no longer appear in the event picker — only open events are selectable.
-- Self-service kiosk: entering an email or phone number that matches an existing account now autofills the visitor's name, the other contact channel, and notification preference, instead of requiring staff to re-enter details already on file.
+- Self-service kiosk: added a "Look up existing account" search field (by email or phone, triggered only by Enter or the Search button — never as-you-type) that autofills a returning visitor's name, contact details, and notification preference from their exact matching account, instead of requiring staff to re-enter details already on file.
 
 ## [1.3.0] - 2026-07-27
 
diff --git a/frontend/src/app/self-service/page.tsx b/frontend/src/app/self-service/page.tsx
index 32a5a27..45af3c9 100644
--- a/frontend/src/app/self-service/page.tsx
+++ b/frontend/src/app/self-service/page.tsx
@@ -113,8 +113,12 @@ export default function SelfServicePage() {
   const [createAccount, setCreateAccount] = useState(false);
   const [visitorPassword, setVisitorPassword] = useState("");
   const [accountExists, setAccountExists] = useState(false);
-  const [checkingAccount, setCheckingAccount] = useState(false);
   const [quantities, setQuantities] = useState<Record<string, number>>({});
+
+  // ── Account lookup (search-by-email/phone) state ──────────────────
+  const [lookupQuery, setLookupQuery] = useState("");
+  const [lookupLoading, setLookupLoading] = useState(false);
+  const [lookupMessage, setLookupMessage] = useState<string | null>(null);
   const [formLoading, setFormLoading] = useState(false);
   const [formError, setFormError] = useState<string | null>(null);
 
@@ -416,6 +420,8 @@ export default function SelfServicePage() {
     setCreateAccount(false);
     setVisitorPassword("");
     setAccountExists(false);
+    setLookupQuery("");
+    setLookupMessage(null);
     setFormError(null);
     setCurrentRegistrationId(null);
     setCurrentUserId(null);
@@ -431,44 +437,51 @@ export default function SelfServicePage() {
     };
   }, []);
 
-  // ─── Check whether an account already exists for the entered email/phone, and
-  // autofill the rest of the visitor's details from it (name, the other contact
-  // channel, notification preference) so staff don't have to re-ask for info
-  // already on file. Only fills fields that are still blank — never overwrites
-  // whatever the operator is actively typing. ──
-  useEffect(() => {
-    const email = visitorEmail.trim();
-    const phone = visitorPhone.trim();
-    if (!supervisorToken || (!email && !phone)) {
-      setAccountExists(false);
-      return;
-    }
-    const handle = setTimeout(async () => {
-      setCheckingAccount(true);
-      try {
-        const params = new URLSearchParams();
-        if (email) params.set("email", email);
-        if (phone) params.set("phone", phone);
-        const data = await apiFetch<{
-          exists: boolean;
-          user?: { name: string; email: string | null; phoneNumber: string | null; notificationPreference: "email" | "whatsapp" | "both" } | null;
-        }>(`/api/users/check-exists?${params.toString()}`, { authToken: supervisorToken });
-        setAccountExists(!!data?.exists);
-        if (data?.user) {
-          const found = data.user;
-          setVisitorName((prev) => (prev.trim() ? prev : found.name));
-          if (found.email && !email) setVisitorEmail(found.email);
-          if (found.phoneNumber && !phone) setVisitorPhone(found.phoneNumber);
-          setNotificationPref(found.notificationPreference);
-        }
-      } catch {
+  // ─── Explicit account lookup — only runs when the operator submits the search
+  // (Enter or the Search button), never on keystroke. Matches exactly against a
+  // single email or phone value and only ever returns that one matched account
+  // (or nothing) — never a broader/fuzzy match. ──
+  async function handleLookup() {
+    const q = lookupQuery.trim();
+    if (!q || !supervisorToken) return;
+    setLookupLoading(true);
+    setLookupMessage(null);
+    try {
+      // Classify the query as email- or phone-shaped and send it as only that param —
+      // sending the same raw string as both could let digits embedded in an email
+      // (e.g. a numeric local-part) get misread as an unrelated phone number.
+      const params = new URLSearchParams();
+      if (q.includes("@")) params.set("email", q);
+      else params.set("phone", q);
+      const data = await apiFetch<{
+        exists: boolean;
+        user?: { name: string; email: string | null; phoneNumber: string | null; notificationPreference: "email" | "whatsapp" | "both" } | null;
+      }>(`/api/users/check-exists?${params.toString()}`, { authToken: supervisorToken });
+      if (data?.exists && data.user) {
+        const found = data.user;
+        setVisitorName(found.name);
+        setVisitorEmail(found.email || "");
+        setVisitorPhone(found.phoneNumber || "");
+        setNotificationPref(found.notificationPreference);
+        setAccountExists(true);
+        setLookupMessage("Account found — details filled in below.");
+      } else {
         setAccountExists(false);
-      } finally {
-        setCheckingAccount(false);
+        setLookupMessage("No matching account found.");
       }
-    }, 400);
-    return () => clearTimeout(handle);
-  }, [visitorEmail, visitorPhone, supervisorToken]);
+    } catch {
+      setLookupMessage("Lookup failed. Please try again.");
+    } finally {
+      setLookupLoading(false);
+    }
+  }
+
+  function handleLookupKeyDown(e: React.KeyboardEvent<HTMLInputElement>) {
+    if (e.key === "Enter") {
+      e.preventDefault();
+      handleLookup();
+    }
+  }
 
   // Existing accounts are linked automatically — never show the "create account" toggle for them
   useEffect(() => {
@@ -639,6 +652,34 @@ export default function SelfServicePage() {
               <p className="text-gray-500 text-sm mt-1">{fmtDate(selectedEvent.startDate)}</p>
             </div>
 
+            <div className="mb-5 border border-gray-200 rounded-xl p-4 bg-gray-50">
+              <label className="block text-sm font-medium text-gray-700 mb-1">Look up existing account</label>
+              <p className="text-xs text-gray-500 mb-2">Search by email or phone number to fill in a returning visitor&apos;s details.</p>
+              <div className="flex gap-2">
+                <input
+                  type="text"
+                  value={lookupQuery}
+                  onChange={(e) => setLookupQuery(e.target.value)}
+                  onKeyDown={handleLookupKeyDown}
+                  className="flex-1 border border-gray-300 rounded-xl px-4 py-3 text-base focus:outline-none focus:ring-2 focus:ring-blue-500"
+                  placeholder="Email or phone number"
+                />
+                <button
+                  type="button"
+                  onClick={handleLookup}
+                  disabled={lookupLoading || !lookupQuery.trim()}
+                  className="px-5 rounded-xl bg-gray-700 text-white font-medium hover:bg-gray-800 disabled:opacity-50 transition"
+                >
+                  {lookupLoading ? "Searching…" : "Search"}
+                </button>
+              </div>
+              {lookupMessage && (
+                <p className={`text-sm mt-2 ${lookupMessage.startsWith("Account found") ? "text-green-700" : "text-gray-500"}`}>
+                  {lookupMessage}
+                </p>
+              )}
+            </div>
+
             <form onSubmit={handleRegister} className="space-y-5">
               <div>
                 <label className="block text-sm font-medium text-gray-700 mb-1">Full Name <span className="text-red-500">*</span></label>
@@ -806,7 +847,7 @@ export default function SelfServicePage() {
               {/* Account creation toggle — hidden once we know an account already exists */}
               {accountExists ? (
                 <div className="border border-green-200 bg-green-50 rounded-xl px-4 py-3 text-sm text-green-700">
-                  An account with this email/number already exists — we&apos;ve filled in their details below, and you&apos;ll be registered using that account.
+                  An account with this email/number already exists — you&apos;ll be registered using that account.
                 </div>
               ) : (
                 <div className="border border-gray-200 rounded-xl px-4 py-4">
@@ -819,9 +860,7 @@ export default function SelfServicePage() {
                     </div>
                     <div>
                       <p className="font-medium text-gray-800">Create an account</p>
-                      <p className="text-sm text-gray-500">
-                        {checkingAccount ? "Checking for an existing account…" : "Save your details for future events"}
-                      </p>
+                      <p className="text-sm text-gray-500">Save your details for future events</p>
                     </div>
                   </label>
                   {createAccount && (