Dreading team build day but don’t think I can not attend

I wouldn't get an ice bath full stop.
I wouldn't be in swimwear in front of 99% of my friends. Colleagues? Not a hope in hell. Never.

It’s not entirely clear how well you get on with your colleagues OP so how you choose to handle it will be affected by that too.
If you get on well with them, when they start talking about the sauna chip in with ooh glad you reminded me I’ll make sure I’ve got my book, much as I love you all I’m not sitting in my undies with you! (That’s how someone in our team would handle it, and I’d wager a large sun of money they’d have company in readers corner!). If not, as others have suggested, just say the last time you had a sauna it made you unwell - faint, or skin complaint flared up, so you’ll see them when they come out.
I do really feel for you. I’m currently WFH because the team have decided to have Christmas dinner in a place where I’ve had food poisoning the last 3x I went. I joked I’d stay back so if everyone went down with it at least there’ll be someone to switch the lights on in the morning but I certainly won’t be sitting with them in the office when they come back.

I’m shocked that anyone would think this is appropriate.

Anyway, you can just say no. You hate getting wet and will be sitting down with a coffee and a book whilst others are sweating in the sauna.

I guarantee that as soon as one of you puts their foot down, others will follow.

Bottom line @Oldtown2 is no workplace can force you to put on a swimsuit and sit in a sauna.

You’re not a playboy bunny & you have rights in the workplace. I’m surprised any manager would think this a reasonable request and if you get negativity for not doing it I would be complaining to HR. They are skating on very thin ice.

It's not a very inclusive activity is it as it will exclude people who can't take part due to cultural, religious or personal reasons because of the swimsuit dress code. The activity also excludes people with health concerns from joining in the spa activities.

I'd email HR citing the reasons above and tell them that for Christmas 2026 the activities have to be more inclusive. Plus, it's giving the office pervert a chance to oggle freely which I'm sure HR won't be happy about.

It’s a real shame that that kind of thing often triggers ear infections for you, isn’t it OP?

seriously though, don’t take a swimming costume, say I don’t feel comfortable with this activity, so I’m going to sit this part out, ( write up some of the things you all talked about in the morning if it helps you feel more justified in doing that during work time) have fun and I’ll see you all this evening

@Oldtown2
Bloody hell!!!!
Absolutely no chance would I get my kit off in front of my colleagues.

Bow out gracefully
You: "Im sitting this one out"
Work: "oh why? C'mon, it'll be fun"
You: "you go have fun🙂"
Work: "C'mon everyone's doing it"
You: "nope, enjoy, see you in a bit" (walks away)

If anyone says anything afterwards:
"Not my cuppa tea but hope you all had fun"

Might be easier for me because I do nothing that I don't want to do and I'm more than able to say no and bugger the consequences.

Be firm, it sounds like a nightmare

I don't know what all the wailing is about - the OP has every right to just say No.

'Hi Dave. No I won't be getting into a sauna with you and the rest of the guys. I'll come on the non-sauna related activities but this is so inappropriate I don't even have words'.

Say you have high blood pressure & your doctor advised you not to go to saunas so you didn’t pack your swimming costume but will quietly read a book instead while they’re at the sauna & meet up afterwards.

This is the way to go OP, you’d love to go but actually can’t do saunas. If someone asks why say it’s against medical advice and don’t elaborate. You think it’s a great idea and didn’t want to spoil anyone’s fun so didn’t say anything earlier! Only down side is they might think you’re pregnant.

Or just say it's not your cup of tea, you cant think of anything worse and you'll just watch them.

So inappropriate. And so many reasons people wouldn’t want to do this. What if someone is in early stages of pregnancy?

Tell them you have a UTI. I'd love to do something like this but I suffer from UTIs and wouldn't be able to sit around in a soggy swimsuit. Just say you'll watch them but you cant get in.

I didn’t realise until I saw someone else do it that it is fine to just not take part in some of team building, you can say at the time “I’m not doing this part” you don’t have to give reasons or make excuses and no one has any right to ask questions or try and pressure you into it or make a fuss. Like I don’t think it detracts from their experience if I don’t take part. The sky doesn’t fall in, I won’t get fired, I think people were probably a bit jealous when I just started saying no to certain things. Hope you manage to be assertive. This would also be my worst nightmare. And I swim a lot and have seen some colleagues at the pool. Also I suffer from heavy and unpredictable periods so not even sure how insensitive you’d have to be to think it’s ok to have this as a team building as statistically there is likely to be one in your team who also has this problem.

If it's just one of the activities, say you don't fancy that one, take a book and a thermos of coffee and sit it out. I wouldn't fancy it either. Not worried about being in a cozzie, but it's just not something I'd want to do with colleagues. Don't take swimwear, don't make a big deal out of it and wave at them from a distance!

Exactly the right answer. Do not lie! This could bite you later. Go but don’t participate and just cheer people on.

You seem to be guessing about the day - do you actually know? Have you been told to bring a swimsuit?

This is completely inappropriate. Does HR know?

As someone who used to work in HR i am shocked this has been arranged. Its not appropriate or fair on employees as many will find it uncomfortable. You could always be sick that day.

A sauna with colleagues??! Some employers are so clueless it’s painful.

This! Completely inappropriate 😳

I would just say no. I dont have a costume and its inappropriate. How is it team building is someone us anxious days in advance?

You shouldn’t feel forced to make up a health reason. You can simply say that you won’t be doing the activities organised because you prefer to remain dressed when with work colleagues.

Be glad you don't live in Germany because it's mandatory to be naked in saunas!

A sauna isn’t an appropriate team building activity in the workplace. Just decline to take part.

Our work would never plan something like this. It would be an absolute no-no. I would be sick