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Cas Cay

A small mangrove cay in the St Thomas marine sanctuary, reached by kayak.

Updated 3 September 2026

Typecay
WhereSaint Thomas
Nearest cityCharlotte Amalie
Best seasonDecember to April
Time to allowHalf a day
Getting thereIn the Mangrove Lagoon on St Thomas; kayak or boat from Compass Point
EntryKayak tour fees

Cas Cay sits in the Mangrove Lagoon on the southeast side of St Thomas, inside a marine reserve and wildlife sanctuary, and it is reached by paddling through the mangrove channels from the mainland. The cay has a short trail across it to a rocky shore with a blowhole and tide pools on the windward side, and the lagoon behind is a nursery for reef fish, rays and juvenile sharks.

Highlights

  • The mangrove channels - the paddling route through the sanctuary.
  • The blowhole - the surge hole on the windward rocky shore.
  • The tide pools - the basins on the exposed side of the cay.
  • The nursery lagoon - juvenile fish, rays and sharks in the sheltered water.

When to go

December to April is the dry season with the calmest paddling. Tide governs the channels. Trips run in the morning before the wind builds.

Good to know

Access is effectively by guided kayak tour rather than independently. The windward trail is over sharp rock and needs footwear. Mosquitoes in the mangroves are severe at dusk.

Nearby

Red Hook is northeast, and Charlotte Amalie is west.

Key facts

Area129 km² (50 sq mi)
Location18.3069° N, 64.8651° W · map

Source: Wikidata, item Q20683466, read on 18 October 2026.

What to pack for Cas Cay

Chosen from what this place is for. Tap a kit for the full checklist.

  • Broken-in walking shoes or boots - Grip and ankle support matter more than looks; never hike in brand-new boots. Find on Amazon
  • Reef-safe sunscreen - High SPF that will not bleach the coral you are swimming over. Find on Amazon
  • Quick-dry clothing - Board shorts or synthetics that shrug off spray and dry fast. Find on Amazon
  • Binoculars - The single best wildlife tool - even a compact pair transforms a sighting. Find on Amazon

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Opening times, ticket prices and seasonal closures change - check the official source before you go: official site.

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