Jeff Fraser from Gluten Free Tamarindo has written a blog for Tamarindo Beach Info with his favourite places to eat in Tamarindo that offer gluten-free options. Here are a few of his recommendations.
The Santa Rita Cafe is a fantastic spot for a gluten-free lunch. They offer sandwiches on Udi's gluten-free bread and they are amazing. I've had the vegetable sandwich and the chicken sandwich so far and have not been disappointed. This is also one of the safest places in Tamarindo to eat gluten-free. The owner is highly knowledgeable of gluten-free food safety and is very careful to avoid any chance of cross contamination. If you follow a gluten free diet, this restaurant is a must visit.
If you are looking for great sushi in Tamarindo, Bamboo Sushi Club is the place to go. They don't have a gluten-free menu and the staff are not super knowledgeable about gluten-free items, but they do offer Kikkoman gluten-free soy sauce, you just have to ask for it. Just be careful when ordering, as there are a few items that contain tempura even though it's not mentioned on the menu - it's best to ask just to be safe.
Cala Moresca Restaurant, located at the Cala Luna Boutique Hotel, is another restaurant in the Tamarindo area with gluten-free items highlighted on their menu. There is a pretty good selection and the staff are reasonably well aware of gluten-free needs. If you are visiting for the fabulous breakfast buffet, you can even get gluten-free pancakes and corn tortillas instead of bread. They also don't line their bacon serving dish with bread to soak up all the grease (a nice change from a lot of buffets I have visited).
The Surf Shack is one of the best places for a burger in Tamarindo. The peanut butter and bacon burger is especially fantastic. They don't have any specific gluten-free options but you can order any burger without a bun. If you bring in your own gluten-free buns (Udi's buns are available at the Auto Mercado, just outside of Tamarindo) they will also prepare an burger for you, complete with toasted bun.
Antichi Sapori was the first restaurant I found in the Tamarindo area that serves gluten-free pizza. In fact, they can do almost anything on the menu gluten-free, including pasta and focaccia sandwiches. They need 4-5 hours notice to prepare your meal so call ahead at +506-8566-6596. The owner speaks pretty good English and understands gluten-free, just make sure that if you are speaking with the staff that they fully understand that you are wanting to order a gluten-free pizza (or other meal). It's not a common order so it might get miscommunicated.
The last thing I expected to find in Tamarindo was a restaurant offering gluten-free waffles, so I was pleasantly surprised to find Coffee & Waffles on a walk to the rotunda. They offer quite a few different flavors of waffles, from the classic waffle and a side of maple syrup, to a waffle topped with Nutella and peanut butter. The service was fast and friendly and our table had an amazing view of the waves breaking on Tamarindo beach.