The Greek Islands are one of those places where postcards actually look like the real thing—and that feeling is especially pronounced when you’re looking at the idyllic coastlines from the water. A day cruise in Greece isn’t the only way to see the islands, but it’s among the best. You have plenty of options to choose from, too. Take an island-hopping tour of Mykonos, Rhodes, or Hydra. Check out Santorini’s caldera and hot springs. Or simply sit back on deck, relax, and watch the sun go down while you enjoy some traditional Greek snacks. Day cruises in Greece are days well spent.