Here's a link to a webpage about Scuba Diving in St Lucia:

http://www.caribbeanmag.com/search/articles/St_Lucia/Scuba_diving_in_st_lucia.html

Here's an excerpt that includes a list of dive operators:

Divers are tantalized with shallow reefs, amazing wall drop-offs, underwater canyons with big fish and a variaty of marine life.
St. Lucia Dive Operators:

• Dive Fair Helen/Helen Divers Ltd. Scuba diving tours and training.
• Oasis Marigot - Dive packages from this hotel on Marigot Bay.
• Buddies Scuba - Dive shop located on the north side of St. Lucia - located at the waterside landing marina in the second lagoon in side Rodney Bay Marina.
• Dive Fair Helen - located at the Marigot Beach Club in Marigot Bay
• Frog's Diving In St. Lucia - Located at Harmony Suites Hotel at Rodney Bay, in the North of the island, convenient to many of the northern hotels.
• Scuba St. Lucia - PADI Gold Palm Resort. Located at the "beautiful" Anse Chastanet resort. The hotel and dive shop are located in the heart of St. Lucia's Marine Reserve. There is good snorkeling right off shore in a "roped off" area.

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