The 27-year-old woman, who was a Sunshine Coast local, was found by an off-duty lifesaver just after 5am on Thursday and investigators are not treating her death as suspicious.

Based on tide movements, police believe the woman entered the water at Kawana or Caloundra.

Senior Sergeant Matt Campbell said the woman's phone was a "pertinent piece of evidence" and could shed further light on her movements before entering the water.

"What I will seek some community assistance with is finding the phone that belonged to that young girl, we believe that it’s a black S9 Samsung," he said.

"So if anyone in the Kawana or Caloundra beach area comes across such an item, we would be seeking to know that.

"As you can imagine, prior to an incident like this, any kind of communication with anyone could give us a lot better insight into what’s happened."

Senior Sergeant Campbell said the woman's family was "absolutely devastated" and described her death as "a horrible, horrible incident".

The lifesaver who made the grim discovery on the stretch of beach near Lower Neill Street, has been offered counselling.

Police were not able to identify the body until about 8am and initially asked for help from the public who believed they may know who the woman was.

A report will be prepared for the coroner.