Originally in Dutch hands, the outstanding natural harbour was taken over by the British and developed in a major naval base and coaling station.
The principal batteries defending the Harbour of Trincomalee in about 1900 were:
Listing Type : Coaling Station
Location : Sri Lanka
FORT FREDRICK
OSTENBURGH CASTLE
SOBER ISLANDS
Citadel Battery
West Battery
Flagstaff Battery
Eastern Battery
Portuguese Bastion
Cavalier
Ridge Battery
Regent’s Battery
Ostenburgh Point Battery
Arthur Battery, Greater Sober
Wellesley Battery, Greater Sober
12-pdr Battery, Little Sober
The Rifled Muzzle Loading guns installed in 1887 are shown in the table:
| LOCATION | 1887 | 1894 |
| Fort Fredrick | ||
| Citadel Battery | 1 x 7ins RML | 1 x 7ins RML |
| West Battery | 1 x 9ins RML | 1 x 9ins RML |
| Flagstaff Battery | 1 x 9ins RML | 1 x 9ins RML |
| Eastern Battery | 1 x 9ins RML | 1 x 9ins RML |
| Portuguese Bastion | 1 x 7ins RML | 1 x 7ins RML |
| Cavalier | 1 x 64pdr RML | NIL |
| Fort Ostenburg | ||
| Ridge Battery | 1 x 10in RML | NIL |
| Regent’s Battery | 2 x 7ins RML | 2 x 7ins RML |
| Ostenburg Point Battery | NIL | 3 x 6pdr QF, 3 MGs (defence of minefield) |
Trincomalee became a major British Naval Base during World War 2 and anchorage was defended by fixed armaments including 9.2-inch guns, 6-inch gun and Twin 6-pdr guns.