diff --git a/lib/visitor/unique-visitors.ts b/lib/visitor/unique-visitors.ts
index 658019f..f5e23a3 100644
--- a/lib/visitor/unique-visitors.ts
+++ b/lib/visitor/unique-visitors.ts
@@ -8,6 +8,7 @@ import {
 } from "@/lib/visitor/visitor-identifiers";
 
 const VISITOR_SET_KEY = "erika:unique_visitors:v2";
+const LEGACY_VISITOR_SET_KEY = "erika:unique_visitors";
 
 export async function trackUniqueVisitor(headers: Headers) {
   const client = await getRedisClient();
@@ -15,8 +16,23 @@ export async function trackUniqueVisitor(headers: Headers) {
 
   if (address) {
     const { secret } = getVisitorTrackingConfig();
-    await client.sadd(VISITOR_SET_KEY, hashClientAddress(address, secret));
+    const identifier = hashClientAddress(address, secret);
+    const [isLegacyVisitor, isPrivateVisitor] = await Promise.all([
+      client.sismember(LEGACY_VISITOR_SET_KEY, address),
+      client.sismember(VISITOR_SET_KEY, identifier),
+    ]);
+
+    if (isLegacyVisitor) {
+      // Keep the legacy visitor in the old total without counting a revisit twice.
+      if (isPrivateVisitor) await client.srem(VISITOR_SET_KEY, identifier);
+    } else {
+      await client.sadd(VISITOR_SET_KEY, identifier);
+    }
   }
 
-  return client.scard(VISITOR_SET_KEY);
+  const [legacyCount, privateCount] = await Promise.all([
+    client.scard(LEGACY_VISITOR_SET_KEY),
+    client.scard(VISITOR_SET_KEY),
+  ]);
+  return legacyCount + privateCount;
 }