The pair helped the women’s 4x200m freestyle relay team to a placing of seventh at the world championships early yesterday.
The Kiwis finished in 7min 59.08sec.
Fairweather led off and, while the top three cleared out, her impressive time of 1min 58.24sec put New Zealand right in the mix with the rest of the field.
Eve Thomas dipped just beneath the 2min mark too, before Deans clocked in just over 2min to leave the Kiwis at 5min 58.98sec.
Laura Littlejohn finished off, just over 2min as well.
The United States, spearheaded by Katie Ledecky, won gold in 7min 41.45sec.
They were trailed in by Australia, which finished 2sec back.
Canada claimed bronze on the back of a lightning start from Summer McIntosh (15).
Her time of 1min 54.79sec set a junior world record, and would have been fast enough to win gold in the individual race had she competed in it.
From there the team held off a surging China team to take its podium spot.
Fairweather raced in the 4x100m mixed freestyle relay last night.
Dunedin’s Ruby Heath gets her first action on Monday night, in the 5km open water swim.
