Trongisvágsfjørður is the fjord at whose head Tvøroyri sits, a narrow inlet that cuts several kilometres into the east coast of Suðuroy. The name means something like "the narrow bay's fjord," which describes it accurately — the walls are steep and green, dropping directly into dark water, with the small settlements of Froðba and Øravík on the opposite shore visible from the Tvøroyri waterfront.
The fjord is best appreciated from the water, either by taking the ferry from Krambatangi across to Tórshavn, which passes out through the mouth, or by renting a kayak in summer if the conditions are settled. The road that runs along the northern shore toward Froðba offers good views back across the water to Tvøroyri. Birdlife includes fulmars nesting on the lower cliffs and eiders on the water.