Should I ask my fiance's two sisters to be bridesmaids?

Seems like the groom could provide some input.

It seems like it’s not obligatory. And if they are reasonable, you shouldn’t have to worry about their reaction. And if they aren’t reasonable, at least they live in the UK!

Ask who you want. I would ask people I knew and liked. People think of it as a honor to be a bridesmaid, but I consider it a pain. You have to pay for the shower, you have to chip in for a large gift at the shower, you have to pay for this fancy stupid dress you’ll most likely never wear again, plus the shoes, etc., PLUS at the reception, when everyone is drinking and eating at the cocktail hour, you are called off for photos. It’s such a pain, and yet girls swoon over being asked to be a bridesmaid.

Something I learned later in life:

You should do what feels best to you in this situation.

Are you having receptions in both the UK and US? Let them be a big part of the reception in the UK.

I doubt they’d expect to be asked or take offense not being asked but as others have written, it’s what you are comfortable with. Family who are excited to meet you and get to know you won’t pull petty pouts about being in the wedding party or not.

Will his family be flying over to attend the wedding?

Include them in some other way. Maybe ask them to do a reading? That way they’re a part of the wedding, but you don’t have to have a roaring headache over how to coordinate with people overseas.

@Nimis’ idea was great.

Your bridesmaids are your friends standing up for you, not a family obligation to his side. Many brides have their sister-in-laws to be, but that’s when they are close and friendly before the engagement.

Besides, four attendants each for a small wedding is too much.

Hmm, well they should be invited, but not necessarily as bridesmaids. I thought bridesmaids were generally people who were well-known friends of the bride.

Just invite them as guests.

Although I agree that bridesmaids should be the people you are closest to, simply put, you may want to consider how traditional his family is. Even though it may seem unnecessary to us it might be worth looking into just in case in order to not start off on bad terms

They are already spending an enormous amount of money to come to your wedding. I would not add to their expenses by asking them to be in your wedding. They may be thinking “I hope I don’t have to be in the wedding, I can’t afford it.”