It wasn't terrible getting to San Pedro. You would fly into Belize city and than taxi to the municipal airport where you take a 20 minute flight to San Pedro. If I remember they left every 90 minutes or so during the day. There are also probably flights from the international airport there as well but we choose to use the municipal airport. There probably would also be water transportation to get there as well but I have never used that so I can't speak to it. Oh and we didn't dive but the snorkeling in the national park was probably the most amazing in the Caribbean.

Went to google. Here is more info. https://ambergriscaye.com/help/article-64.html