A spokesman for the pool, part of Sundsvall's municipal leisure centre, said that employees there had decided they would not act if women tried to bathe semi-naked.
"We're used to naked people. Nobody cares," Per-Erik Ulander told local paper Dagbladet, adding that women could still be asked to cover up if other bathers take offence.
The Bara Bröst network - which translates both as 'bare breasts' and 'just breasts' - last year started its campaign for women to be allowed to swim without tops by stripping off at a pool in Uppsala. The protesters were ejected from the pool. Since then, campaigners have launched protest actions across the country, which have usually resulted in them being asked to leave.
The decision by the pool is the first real victory for the group, which has around 40 members.
"This is positive," said group member Ragnhild Karlsson to news agency TT.
The group faced a setback in November after the Swedish sexual equality ombudsman (Jämo) ruled that it was not discriminatory for women to be banned from bare-breasted bathing. Karlsson rejected the ombudsman's conclusions:
"The only sensible thing is to have the same rule for men as for women. If women can't be without a top, then men shouldn't get away with it either," she said.