My husband and I will be celebrating our 20th anniversary in St. Maarten/St. Martin. We love seafood, fish, pork & chicken. Where is a romantic place to have a nice anniversary meal.

In what area are you staying? French side or Dutch side?

There are many places to choose from..both French or Dutch side.
and everyone of course has their favorite restaurant.
Personally I love the restaurants in Grand Case. the ones on the beach side have lovely romantic settings, with excellent service, and the food is always good.
I like Le Tastevin but there are many others to choose from also.
If you like Italian, I cna also recommend Spiga in Grand Case.
It is not on the water but is in a charming little West Indian house .
The food and service are excellent.
The owner and hostess Lara will do everything to make your dinner a memorable one.
Anopther excellent restaurant in a lovely setting is in the Port Royale Marina in Marigot. It is called Tropicana. Ask for a small outside table on the water ( if the weather is good).
The food there is wonderful as is the service. Tropicana is one of my favorite restaurants on the island.

We are staying in Oyster Bay Resort

What are your opions of Le Chanticlair?

Le Chanticlair is also excellent although I like Tropicana better.
another nice restaurant right near you is Daniel's by the Sea..
It is Mr. Busby's by day and Daniel's at night with fabulous italian cuisine and a great setting.