1806
In May, 1806, a draft of one hundred and twenty-four men joined from the second battalion, and a few volunteers from the eleventh regiment.
1807
On the 24th of January, 1807, the regiment was suddenly embarked on board the fleet; but after a short cruise returned to Barbadoes, from whence it was removed to Grenada in April.
The court of Denmark having united with France, in hostilities against Great Britain, an expedition was prepared against the Danish islands of St. Thomas and Santa Croix, and the Fifteenth embarked from Grenada to take part in this service. These colonies surrendered on being summoned, and loss of life was thus prevented.
1808
In July, 1808, a draft of six serjeants and two hundred and ninety-three rank and file joined from the second battalion.
In November and the early part of December, the regiment lost about one hundred and fifty men from the effects of the climate of the West Indies.
1809
The regiment joined the expedition under Lieut.-General Beckwith, which sailed from Carlisle-bay, Barbadoes, on the 28th of January, 1809, against the island of Martinique. The first division landed in Bay Robert, and the second near St. Luce and Point Solomon. The enemy's force was numerous, and some sharp fighting occurred, in which the regiment had the honor to distinguish itself, and had several men killed and wounded. The conquest of the island was achieved in a few weeks, and Lieut.-General Beckwith stated in his public despatch,—'The having commanded such an army will constitute the pride of my future life. To these brave troops, conducted by Generals of experience, their king and country owe the sovereignty of this important colony; and I trust, that by a comparison of the force which defended it, and the time in which it has fallen, the present reduction of Martinique will not be deemed eclipsed by any former expedition.'