Where do partners of wedding party hang out before the ceremony?

They should be able to occupy themselves until the wedding. If it's destination, they can stay at the hotel or grab a bite nearby. If it's local, they can simply stay home until the time they should arrive.

When I was a bridesmaid in my friend's wedding, my husband hung out in our hotel room, read, watched TV, etc until it was time for him to get dressed for the wedding. If the significant others all know each other, they could organize something for them to do as a group (golfing, brunch, hiking, shopping, etc) before it's time to go to the ceremony.

Either of those can work. If it’s just one or two SOs sometimes the bride will mention that they are welcome to hang out, watch photos etc. But it’s not obligatory. It’s their responsibility to figure out how to occupy any extra time.

All the weddings I’ve been in, the SOs of any attendants would make their separate way there at the appropriate time for a guest. I’ve never had an SO hanging out at the venue with the bridal party.

In my experience, they hang out at the hotel or wherever they're staying. They're guests, they only need to arrive when the other guests do.

In my experience, typically they just do their own thing until it’s time for them to arrive as a guest. For my wedding, my sister in law’s now wife (then fiancé) hung out in the bridal suite with us. They lived out of state and she didn’t know anyone and didn’t want to spend so many hours alone before the wedding.

Honestly it's going to depend.

For my wedding, my husband's sister (bridesmaid) and my husband's brother (groomsman) rented an Airbnb together and their significant others hung out at the Airbnb most of the time. My brother-in-law was nice enough to grab Dunkin Donuts for us when my husband's sister texted him that we needed breakfast. My sister's husband hung out with my grandfather (grandmother was getting hair and makeup done with me) most of the time. I think they went to some museum in town and had lunch together. The rest of the bridal party was either single, both members of the couple were in the wedding, or their significant other didn't attend due to limited vacation time.

For my husband's brother's wedding, I only know what I did while my husband was with the other groomsmen. Unfortunately, my brother-in-law and his wife didn't really plan out where my brother-in-law and the groomsmen would get ready for the wedding so the night before at the rehearsal my husband asked where he needed to be to get ready and his brother had no clue. At that point, my husband offered to let him and the groomsmen use our hotel room. This meant at about noon I had to leave the hotel room. The only people I knew were either not in town yet or were getting ready for the wedding so this left me alone in a strange town eight hours from home with nowhere to go. I was extremely upset. My husband's sister and I were supposed to be hanging out together, but she ended up offering to assist picking up the dessert for the wedding. She didn't communicate this to me so after I called her and my mother-in-law and couldn't get a hold of anyone I left the hotel and found the nearest mall. I ended up just walking through a mall and then decide to get my hair done so it would look nice for the wedding. It definitely wasn't what I thought I'd be doing while waiting. If I had known I wasn't going to have a hotel room to just chill in or my sister-in-law to hangout with I would've researched for things to do in the area in advance.

From my experience the partners hang out in their own hotel room if the couple is staying over night or home if the wedding is local. But leave it to the couple to decide how it will be handled. I d just say what time you need your bridesmaids with you.