You can swim between Petit St Vincent and Petit Martinique but they straddle the border between Grenada and St Vincent and the Grenadines. The Martinique Channel is the official dividing line between the two countries, but boats and people move fairly freely between the two countries here, making it easy enough to visit Petit Martinique and this cache by taxi boat from either Union Island and Petit St Vincent (SVG) or by ferry from Carricou and Grenada (Grenada).
Petit Martinique has a population of around 500 and a small village where souveniers, supplies and food can be bought. Petit St Vincent nearby is a private island but anyone can visit the upscale restaurant and bar. Nearby Union Island and Carricou are launching points for some of the best snorkelling in the region.
This cache, located a short walk from the docks at Petit Martinique, is a quick find overlooking the border between the two archipelgo nations.