AIBU to expect a cleaner family bathroom when staying with in-laws?

I absolutely hate staying with other people for this reason. The exception is at my best friend's house, as it's like a fantastic B and B, all clean, with lovely towels, and you feel spoiled. I only stay in hotels now as I'm not fanatical about cleaning but sometimes staying with family is just too close...cheap Travelodge/Air B and B?

Well, this is not a minor dealbreaker for me.

I don't want to tiptoe around dirty, damp clothing and sanitary towel wrappers.

Urgh. Pigsty.

I think the key thing here is - I do think there's an expectation that whoever has invited a guest does a quick tidy up by inviting them you're extending hospitality.

However there is no evidence SIL is the one who invited them. Therefore this isn't her job. Also, it's her brother - if she didn't invite him I don't see why she has any obligation to clean for him. She's not his servant. It's her home (and presumably formerly his home).

Don't like it, you don't have to stay.

So was I. Quick wipe of the bathroom and the kitchen. Even for family I think it’s common decency.

I don’t understand why most of MN seems to think this woman child is in the right just leaving litter and laundry all over the floor when there’s guests (even if related). It also makes me wonder about her hygiene if she isn’t washing her hands after the toilet, especially after handling soiled period pads (you assume based on new wrappers on floor). Grim.

Sounds grim. When I have guests I minimise my stuff in the bathroom so guests have somewhere to put things. I certainly wouldn't leave out everything or my clothes for that matter! I give each guest their own towel to use too. I also leave out a cloth and spray so if anybody wants to give the shower/bath/basin a quick going over between uses they can.

I agree100% with this.
When going to live with relatives, I'm just grateful that they would allow us to stay and host us.
Instead of moaning, I would tidy up and buy some soap or handwash to put there for the duration of my stay.
I would just use my own towel aswell.
Afterwards, its up to them how they keep their bathroom.

Maybe she's depressed at the breakdown of her relationship and doesn't have the mental resilience for cleaning right now. Or indeed judgemental house guests.

Just buy some soap and ask MIL for hand towels FFS. It's not a big deal.

Further context, how much cleaning does your DH do? Perhaps they are all of the same ilk?

volunteer to clean it! i’m sure they will love that

This. It's not a hotel.

Maybe she didn't want you to visit? Maybe she doesn't want to share the bathroom? Maybe she simply doesn't feel like cleaning the bathroom right now just because you're visiting? Presumably her brother is also capable of cleaning and obtaining soap?

Why can't you use the bathroom your H's parents use since they're presumably the ones who invited you?

SIL sounds lazy and inconsiderate. I'd be mortified if someone wrote this post about my bathroom (although they wouldn't as I have some basic idea of how to make a bathroom look for guests!).
It's for your DH to deal with. If it were me I'd bring the rubbish to an obvious bin like a kitchen one to throw away, bring in the wet used towel and ask where to put it (e.g. washbasket/washing machine) and ask if there's some spare handwash and a couple of hand towels.
She can take that however she wants to.

I always take my own bar soap anyway (I hate plastic bottles) and TBH I’d just tidy it up.

This.
I was always made to make my brother&Sil's bed before they came to stay at my parents house (even though I didn't live in the house either). And "run a cloth around the basins". Like hell did my brother do anything before I ever arrived at my parents house.
OP, would your husband clean the bathroom for his sister if it was the other way around?

I said that her brother should clean it and then ask SIL to keep it that way too.

i.e. the responsibility of keeping it tidy should belong to those who use it.

I would stop going. It sounds disgusting.

This.
Also I take my own toiletries and towels when staying with family or friends.

Maybe SiL is a chaotic ADHD type who does not mean to be this way but is out of control.

It's DHs family, tell him to clean the bathroom and tell his sister to not leave her rubbish lying around in the bathroom!

Should she have tidied it? Yes
Is it her brother's place to lecture her in her own home? No

Id just roll my eyes and ask mil where the towels are and has she any spare hand wash.

My bathroom usually has mounds in family washing basket

Peak mumsnet.

I was brought up to clean up before visitors come, I guess not everyone was!

For me a clean bathroom with towels and some hand-washing materials are basic requirements for visitors. It may usually be the sister's home and bathroom but if you were invited to come and stay - which, I'm assuming you were - then this isn't very welcoming.

I would get a bin, hand towels, handwash, rubber gloves, sink and bath and toilet cleaner etc and just put it all in there. Then’d I’d clean it. I would not give verbal feedback except to say you are helping out.

Yes, it’s grim. I keep the communal bathrooms very tidy when we have house guests, but I’m always a bit appalled going to other people’s houses. Actual balls of pubes blowing about on the floor and dust that looks like it’s been there 3 years. Our house is very lived in and my standards are quite low, but I take 5 minutes to clean the bathroom before people get there and I keep it picked up as best I can.

She sees that as her personal space and she doesn’t want you in it. It’s not a guest bathroom in her eyes and it’s not for you insist that it is.

Your options are to clean it (but fully expect her to re-mark her territory) or to stay elsewhere/go home.