There are several beaches a short drive away from Tramonti.
1. The main beach in Cabo San Lucas is Medano Beach. This is a swimmable beach that is very busy and has lots of vendors. You'll also find lots of fun beach bars here and great people watching. You can bring your own stuff and hang out, head to a beach bar OR take advantage of the amenities at Pueblo Rose or Los Cabos
2. The pacific beach is beautiful but not swimmable. You can head to Pueblo Sunset Beach or Pacifica if you want to go to this beach.
3. You could also take an uber to Santa Maria or Chileno Bay. These are beautiful beaches and great for swimming/water activities but they don't have amenities so you'll have to pee in the water :)