WA could be without a locally-based swimmer in the national squad following Blair Evans' decision to head interstate to continue her career.

Evans, 21, an Olympic silver medallist from the 4x200m freestyle relay at the London Games, announced today she would be moving to Queensland to train.

"The news is out, I'm moving to QLD for a fresh perspective on my swimming!" Evans tweeted today.

"A very hard decision but looking forward to what comes next! The support from family and friends and also @InsideWAIS has been incredible. Can't thank them enough!"

Evans was among four WA swimmers to represent Australia in London. Sally Foster and Tommaso D'Orsogna were based in Canberra while sprinter Eamon Sullivan was part of Grant Stoelwinder's Sydney squad.