The best replacement for wetsuit is drysuit.

The best alternatives to wetsuit are rated as following:
★★★★★  drysuit
★★★  tri suit
★★  waders
★★  rash guard
★★  no wetsuit
★★  swimsuit
★★  wetsuit
★  drysuit scuba
★  jumpsuit
★  semi dry
★  drysuit surfing
★  dive skin
★  rashguard
★  springsuit
★  sleeveless
★  swim skin
  trisuit
  wet suit
  spring suit
  surfing wetsuit
  regular wetsuit
  skin suit
  half wetsuit for first triathlon
  rip curl
  bayside wetsuit
  semi drysuit
  pull buoy
  5mm wetsuit
  back zip
  tyr
  dry suit
  surf wetsuit

Your alternative for wetsuit is not listed? Suggest!
Speaking about wetsuit, one probably shouldn't forget about buoyancy.

Other search terms related to wetsuit and their ratings are:
★★★★★ buoyancy
You have in mind a companion for wetsuit and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of wetsuit in all years. Click on graph for more.
wetsuit
drysuit
tri suit