Land based snorkeling on Isabela island?

Hey all! I’m going to be on Isabella island for 2.5 days. Other than right in town, are there any good snorkeling spots that I can get to by either walking, kayaking from town or biking to? Would I regret not getting a tour to Los Tuneles, or Tortuga island? I’m also going diving from Santa Cruz so I’m spending a lot of money already. If i would be badly missing out though, please let me know. I’ve heard Tuneles is amazing but maybe overhyped?