diff --git a/packages/react-native/Libraries/Blob/URL.js b/packages/react-native/Libraries/Blob/URL.js
index c0f496e1954f0d..f4f879a51214b4 100644
--- a/packages/react-native/Libraries/Blob/URL.js
+++ b/packages/react-native/Libraries/Blob/URL.js
@@ -90,11 +90,15 @@ export class URL {
         }
       }
 
+      // Only add trailing slash if URL has no path (just domain)
       if (
         !this._url.endsWith('/') &&
         !(this._url.includes('?') || this._url.includes('#'))
       ) {
-        this._url += '/';
+        const afterProtocol = this._url.split('://')[1];
+        if (afterProtocol && !afterProtocol.includes('/')) {
+          this._url += '/';
+        }
       }
     } else {
       if (typeof base === 'string') {
@@ -170,6 +174,24 @@ export class URL {
     return searchMatch ? `?${searchMatch[1]}` : '';
   }
 
+  set search(value: string) {
+    // Remove leading '?' if present
+    const searchString = value.startsWith('?') ? value.slice(1) : value;
+
+    // Update the internal URL
+    const baseUrl = this._url.split('?')[0].split('#')[0];
+    const hash = this.hash;
+
+    if (searchString) {
+      this._url = baseUrl + '?' + searchString + hash;
+    } else {
+      this._url = baseUrl + hash;
+    }
+
+    // Reset the searchParams instance so it gets recreated with new values
+    this._searchParamsInstance = null;
+  }
+
   get searchParams(): URLSearchParams {
     if (this._searchParamsInstance == null) {
       this._searchParamsInstance = new URLSearchParams(this.search);
@@ -185,10 +207,19 @@ export class URL {
     if (this._searchParamsInstance === null) {
       return this._url;
     }
+
+    // Remove existing search params and hash from the URL
+    const baseUrl = this._url.split('?')[0].split('#')[0];
+    const hash = this.hash;
+
     // $FlowFixMe[incompatible-use]
     const instanceString = this._searchParamsInstance.toString();
-    const separator = this._url.indexOf('?') > -1 ? '&' : '?';
-    return this._url + separator + instanceString;
+
+    if (instanceString) {
+      return baseUrl + '?' + instanceString + hash;
+    } else {
+      return baseUrl + hash;
+    }
   }
 
   get username(): string {
diff --git a/packages/react-native/Libraries/Blob/__tests__/URL-test.js b/packages/react-native/Libraries/Blob/__tests__/URL-test.js
index fc216b05618bdc..72467dc08ebbc7 100644
--- a/packages/react-native/Libraries/Blob/__tests__/URL-test.js
+++ b/packages/react-native/Libraries/Blob/__tests__/URL-test.js
@@ -139,5 +139,33 @@ describe('URL', function () {
     );
     unsortedParams.sort();
     expect(unsortedParams.toString()).toBe('a=first&b=second&c=third&z=last');
+
+    // searchParams.set() should replace values not duplicate them
+    const urlWithSearchParams = new URL(
+      'https://example.com/api/data?foo=bar&baz=qux',
+    );
+    urlWithSearchParams.searchParams.set('foo', 'newFoo');
+    urlWithSearchParams.searchParams.set('test', '12345');
+    expect(urlWithSearchParams.toString()).toBe(
+      'https://example.com/api/data?foo=newFoo&baz=qux&test=12345',
+    );
+
+    //url.search setter should replace search params
+    const urlSearchSetter = new URL(
+      'https://example.com/api/data?foo=bar&baz=qux',
+    );
+
+    urlSearchSetter.search = 'foo=overwritten&hello=world';
+
+    expect(urlSearchSetter.toString()).toBe(
+      'https://example.com/api/data?foo=overwritten&hello=world',
+    );
+
+    //URL constructor should not add trailing slash to paths
+    const urlWithoutTrailing = new URL('https://example.com/path/to/resource');
+
+    expect(urlWithoutTrailing.toString()).toBe(
+      'https://example.com/path/to/resource',
+    );
   });
 });