People getting into SUPing often wonder, do they need wetsuits, what type, how much should they spend, etc.
Everyone is different but here's my general rules of thumb on deciding what to wear. I ask myself how cold is the water, how long will I be out for and if I'm actually going to be falling in.
If I'm just doing a quick SUP down the local beach or harbour and its summer I just wear a pair of board shorts as its no big deal, if I fall in or get cold, as I can just come back in and head home.
If I'm doing a distance SUP or something more remote, I'll wear a 3/2mm wetsuit no matter how hot it is. The reason I do this is because even if its 25 degrees and the last thing I want, is to be sweating in a wetsuit, falling in and getting cold and having hours before I can get back to my car could be dangerous even during the summer. The waters in the UK and Ireland rarely get above 15 degrees even during the height of summer, if for whatever reason you end up swimming for extended periods of time you'll be pretty happy with those few mm of neprene!
The other thing to consider is that summers in this part of the world can have 4 seasons in a day, you need to be prepared if things change. What I normally do is wear the bottom part of the wetsuit and leave the top rolled down.
So unless I'm going SUP surfing in winter when you're constantly falling in I only need a 3/2 mm wetsuit for pretty much all year round. A budget 3/2 mm wetsuit can start from approximately £50 extending up to £400 for your top of the range, bells and whistles suits! You can also bag some great second hand deals online in SUP/SURF facebook groups or even eBAY. Some add ons are, I will wear a hoody over my wetsuit during winter if its really cold and I normally wear wetsuit boots as your feet are the only part of you actually getting wet. You can pick up a pair of boots for around £20-£50.
So in conclusion, I'd recommend buying a cheap 3/2 mm wetsuit and if you've got the cash buy a decent pair of wetsuit boots.