The Reserve Officer School, located in Hamina, Finland, near the southeastern border, is responsible for the training of most Finnish reserve officers.

Hamina is a town and a municipality of Finland. It is located approximately 145 km (90 mi) east of the country's capital Helsinki, in the Kymenlaakso region, and formerly the province of Southern Finland. The municipality's population is 19,534 and covers an area of 1,155.14 square kilometres (446.00 sq mi), of which 545.66 km2 (210.68 sq mi) is water. The population density is 32.03 inhabitants per square kilometre (83.0/sq mi). The population of the central town is approximately 10,000. The municipal language of Hamina is Finnish.