Ynys y Maengwyn, Powys, North Wales.

The Royal Marine Training Group (Wales) set up camps Burma, Iceland, Gibraltar and Matapan around the Mawddach Estuary to train Royal Marines in the art of beach assaults, while the Amphibious School at Tywyn trained those responsible in maintaining the supply lines of such landings.

Burma Camp – A Royal Marine camp at Llwyngwril, built on requisitioned land approximately 68 acres in extent.
Crete Camp - A Royal Marine camp at Barmouth, consisting mainly of requisitioned houses
Gibraltar Camp – A Royal Marine camp at Llanegryn, Tywyn, consisting of a country house and a camp built on requisitioned land approximately 60 acres in extent. Connected with this area was the training area at Llanegryn, covering some 700 acres, under requisition by the War Department.
Iceland Camp - A Royal Marine camp at Arthog, built on requisitioned land approximately 25 acres in extent.
Matapan Camp – A Royal Marine camp at Ynys y Maengwyn, consisting of a country house and a camp built on requisitioned land approximately 25 acres in extent
In 1942, MNBDO II transferred to North Wales. The Royal Marines operated at five locations: Ynys y Maengwyn, Llanegryn, Llwyn-Gwril, Barmouth and Arthog. Their code names were respectively MATAPAN, GIBRALTAR, BURMA, CRETE and ICELAND. It has been suggested that the Royal Marines were stationed in the quieter areas of Wales, in preparation for deployment during the D-Day landing operations for the invasion of Europe as well as Far East operations.
The camps were used to train and re-train men in seamanship for landing craft as crewmen, coxswains and gun crews.
ICELAND camp at Arthog was also used for handling naval craft.