Snorkeling is the best free thing to do on Koh Larn — or it's a paid boat tour to clearer water. Which is right depends on what you want and how much you mind the cost. Here's the honest comparison, with realistic expectations either way (this is the Gulf, not the Andaman — good, not jaw-dropping).

Do it yourself — the case for

Bring your own mask, wade out at the rocky ends of Samae or Tien on a calm morning, and you'll see plenty of small tropical fish over rocks and patchy coral for free. It's flexible — go when and where you like, stay as long as you want — and the shore snorkeling at the right spot is genuinely decent. This is what we recommend for most people.

  • Cost: free (mask) to ~100–150฿ to rent gear.
  • Best spots: rocky points at Samae and Tien; edges of Nual.
  • Catch: you're limited to shore spots, and visibility varies with weather and time of day.

Book a tour — the case for

A boat snorkeling trip (they run from Tawaen and from Pattaya) takes you out to spots with clearer water than you'll reach from shore, usually with gear, a guide and sometimes lunch included. Worth it if you want the best visibility, can't swim strongly enough to reach the rock edges, or just like someone else handling the logistics.

  • Cost: varies — a chunk more than DIY; confirm what's included.
  • Payoff: clearer water, guidance, gear, less effort.
  • Catch: fixed timing, group pace, and it's still Gulf-of-Thailand snorkeling — manage expectations.

How to choose

Confident swimmer on a budget who wants flexibility → DIY from Samae or Tien. Want the clearest water, or aren't a strong swimmer, or want it organised → take a tour. Either way: go early before boats churn the water, bring your own mask if you have one, wear reef-safe sunscreen or a rash guard, and don't touch the coral.

Tip: Try DIY first — a mask costs nothing to pack. If the shore snorkeling whets your appetite, book a boat trip for the clearer water on another day.

The verdict

For most people, DIY shore snorkeling at Samae or Tien is the better-value choice and genuinely good on a calm morning. Pay for a tour when visibility or guidance matters more than money. Full detail on our snorkeling page.