Is the water in Unawatuna, Sri Lanka suitable for snorkeling?

To put it this way, Unawatuna for snorkeling is what you might call "beginner-friendly, but with limited potential."

Let me break it down for you:

Why is it good for snorkeling (especially for beginners)?

Calm Waters: Unawatuna is a crescent-shaped bay, protected by a natural coral reef barrier, so the waves inside the bay are very small. It's like a giant natural swimming pool. You don't have to worry about being tossed around by big waves, which provides a great sense of security for those who aren't strong swimmers or are trying snorkeling for the first time.
Super Convenient: You don't need to take a boat out to sea; you can just walk straight from the beach, swim a dozen meters, and start seeing things. There are plenty of small shops along the shore renting snorkeling gear (masks, snorkels, fins) at reasonable prices, so you can jump in whenever you feel like it.
Something to See: Near the rocks on both sides of the bay, there's still some underwater life. You can spot some colorful tropical fish, and if you're lucky, you might even encounter a leisurely swimming sea turtle. For just experiencing the joy of snorkeling, it's perfectly adequate.

But why do I say it has "limited potential"?

Average Coral Condition: To be honest, Sri Lanka's corals were severely damaged by the previous tsunami, and Unawatuna is no exception. Don't go with the expectation of seeing vast, vibrant, colorful coral gardens like in the Maldives or the Great Barrier Reef. Many of the corals here are bleached or dead, looking a bit "barren."
Water Clarity Depends on the Day: Although the waves are small, the water clarity isn't always great. Sometimes the sand on the seabed gets stirred up, making the water a bit murky. For good visibility, it's best to choose a clear, calm day.

Here's a summary of my advice:

If you're a snorkeling novice, or traveling with children, and looking for a safe place to simply splash around and see some fish, Unawatuna is definitely a great choice. It's easy, relaxing, and can make you fall in love with snorkeling without any pressure.
If you're an experienced snorkeler seeking extreme underwater landscapes and biodiversity, you might be a little disappointed here. Just treat it as a relaxing part of your trip and don't have overly high expectations.

Small Tip: For better snorkeling spots in Unawatuna, you can head to the nearby Jungle Beach, where there are fewer people, and the underwater environment is usually better than the main beach.

Overall, go for it! As long as you manage your expectations and treat it as a pleasant "beach park" experience, you'll have a great time.