To tell my manager I won’t share a room with colleague again?

Well she can do something about the snoring, as in her own words she knows she needs to shift some weight, but she chooses not to.

Did you miss the ‘in her own words’? Or are you just a bit dim?

Well she can do something about the snoring, as in her own words she knows she needs to shift some weight, but she chooses not to.

If you'd bothered to RTFT you'd know that this point was already made and I agreed with it some 20 hours before your overly-dramatic criticism

Oh lovely.
Fat shaming.

You're charming aren't you?

You are absolutely not being unreasonable. This isn't a fun girl's outing. This is a work trip. And if you can't get a good night's sleep and are bothered by the behaviors of your "roommate", that's going to interrupt your workflow.

It was absolutely unprofessional of her to ask for your meal allowance and even more unprofessional of her to eat in the room and not just use it for a soft drink.
She lied to you.
Does corporate allow you to give your dinner allowance does somebody else? Will you get in trouble for this?

Meanwhile talk to your coworker. Tell her you were uncomfortable with letting her buy a soda, and she took advantage of you and lied to you.
It kind of sounds like she doesn't have much self reflection or awareness of her own behavior.
Tell her that the snoring affected your work, the entire situation didnt work for you.
See if she's open to changing or adjusting her behaviors accordingly. If not, tell her youre going to approach hr and
ask for different accomodations because this rooming situation didn't work for you.
There's absolutely nothing wrong with approaching her either.
Meamwhile do a little research on cheaper hotels or airbnbs or things that would save them money but would allow you to have your own accommodations.

Wrong, wrong, wrong. "I am writing to tell you that I will not be sharing a hotel room with ANOTHER COLLEAGUE again." There, fixed it for you. On no account bring another person into this.

Some background here - my role requires regular travel around the UK as the company has various sites. For about 3 nights each month I stay away in a specific location; up until 2024 I always had my own room, a change was then made for financial reasons that I’d need to share with the colleague travelling with me who does the same role.

No issues at all, we got along and she was respectful and we’ve remained friends post her leaving the company recently.

I travelled with her replacement last week, and we shared a room as per process.

Firstly, she jokingly (I thought) said before we left that she is a snorer. She’s not wrong, even with ear plugs I was struggling to get an uninterrupted nights sleep. By her own admission she is a larger lady and she says even her own husband gets on at her. She honestly snored like a man.

Next issue - we have a £30 per night meal allowance. On one of the nights, I visited my cousin who lives in the area and she cooked for me, so I had no reason to use my allowance.

My colleague asked me if she could use it when I got back to the room (about 9pm at this point). Now she’d already had dinner and the restaurant was closed. She said she only wanted it for a soft drink so I said no problem. She then came back up to the room and said they were still doing room service. 20 minutes later the door goes and hot food arrives which she proceeds to eat on her bed, and the smell lingered all night.

A couple of other minor annoyances in terms of time spent in the bathroom and loud phone calls with her husband which she could have taken outside the room/in reception.

She is polite in general, but that was our first trip and I don’t think I could handle monthly stays with her.

AIBU to tell my manager I won’t share with her again?

Don't listen to people who talk about "ground rules", "mention X but don't mention Y", etc. All you need to do is say that "I am no longer comfortable sharing a room with another person". If they push for reason say "I can't get proper rest with another person in the room who I'm not related to, and I expect privacy while travelling on company business".

Well she can do something about the snoring, as in her own words she knows she needs to shift some weight, but she chooses not to.

Yeah as a teacher I was amused by all the comments saying sharing is inappropriate - although sharing a room is one of the main reasons I avoid overnight school trips!

Yanbu.

I know I snore and I wouldn't dream of sharing a hotel room with anyone other than DH who is used to it. It would be horrendously selfish. Quite simply you are entitled to sufficient self-respect that you can and must insist this never happens again.

Dear Manager/HR

I am writing to tell you that I will not be sharing a hotel room with (colleague name) again. It is deeply inappropriate that company policy has put me in this awkward position because telling you why would require me to tell you personal information about (colleague) that it is private to her and so it's not appropriate for me to give further details. I am not complaining about her and none of this affects either of our capacity to do our jobs to an excellent standard which we will both continue to do. However in future all accommodation must be arranged with separate rooms.

Yours sincerely

Well she can do something about the snoring, as in her own words she knows she needs to shift some weight, but she chooses not to.

your employer should not have made you share a room with anyone. But now you’ve done it before you’re going to have to explain why you don’t want to share you HER, whereas up front you would only have had to explain you won’t share a room. Would they have made you share with a man?

I’d stick with the snoring though, and be prepared for them to find you someone else to share with.

If you go in with all those reasons it sounds a bit moany. Stuck with just the snoring.