edit: added better paragraph breaks

Tips:

-Bring ear plugs with you. Try a few kinds to figure out which work best for you. Put them in before things get loud or overwhelming, and take them out after you’ve left the noisy space. You can get concert ear plugs that still allow you to hear conversation but cut some unnecessary background noise. Shooting ear plugs turn down the volume even more than that.

-If the lights indoors bother you, wear a hat or sunglasses if socially appropriate. Or be a weirdo and wear these things even if it’s not socially appropriate.

-Arrange separate transportation home, and give yourself permission to leave early. If you are no longer having a good time, say goodbye to your friends and leave.

-Give yourself breaks. E.g. : Go to the bathroom. I think you commented that you don’t smoke, but you can still try just stepping outside to take a moment. If your friends are cool with you being a little bit different, they won’t mind you going outside for a bit of quiet. Smokers outside, I imagine, would be understanding of you going outside just to get a moment of peace and quiet, since smokers will often take smoke breaks for the peace in addition to the nicotine.

-During your breaks, check how you are doing. Evaluate yourself for signs of stress. Are you having a good time? Would you prefer to be at home? Are you getting the good parts of socializing still? Do you have enough energy in reserve to get yourself safely home, and do whatever you need to do to set yourself up for success the following day? If you are overwhelmed, or on the verge of expending too much energy, make a plan to go home- for example paying your tab, saying goodbye to your friends, and accessing transportation.

-Before you go, make a plan for when you will leave, in terms of time and energy expenditure. I assume you get enough positive social time with your friends to make hanging out with them in a loud place worth it- for a while. Since your friends like bars/pubs, I assume they have a higher tolerance for loud, stimulating spaces. Don’t try to compete with their stamina! Go based on benchmarks that work for you. Become aware of signs of stress and sensory overwhelm for you. Since loud and overstimulating spaces are inherently overwhelming (for us), you will likely be experiencing some stress from the start. So, you want to look for the point where you are stressed, but not so stressed that you are having a horrible time, and leave before the deep overwhelm sets in. Make this plan beforehand, e.g. " I will leave at (certain time), or when I get a mild headache, or when I’m no longer having fun, whichever comes first." Since you will have a plan beforehand, it will be easier for you to take your exit at a point that is good for you, rather than being overwhelmed, shutting down, and staying until your friends leave (which would result in you having a good time until you get overwhelmed, and then having a bad time for the remainder of the time.)

-When planning whether or not to attend a social outing, check your calendar first. Evaluate whether or not to attend not only on whether or not you have the time, but on whether or not you are likely to have the energy. For example, it might help to try to arrange your schedule so that you have a less intense workload on a day of the week when your friends regularly hang out. If you have a lot of tasks in a day that will be overwhelming, you might plan to leave the social situation earlier since your social battery may be lower. Or, if you are so overwhelmed that you will not enjoy being in a bar/pub even with your friends and self-administered accommodations, you can choose not to attend.

-Be aware of peer pressure. If your friends pressure you to do something you don’t want to do, like stay out when you want to leave, make a joke and then do what you want anyways. Socialize based on meeting your social needs. Don’t stay in situations where you are uncomfortable and gaining no benefit from being there. Good friends will respect your boundaries.

-When you return home from socializing, do activities to help you recover from the stimulating environment and social situations. You can think of it like an athlete who needs to hydrate, eat, and rest after working out in order to maintain the benefits of the workout. Socializing takes energy, and so does dealing with a stimulating environment. If you can, set yourself up for success in transitioning from social time back into your regular life by doing things that will help you maintain your energy throughout the week. Examples: Drink water or have your favorite hydrating drink ready in the fridge, have clothes laid out for the next day so you don’t need to do it late at night and can sleep in later, wear noise canceling headphones in your home to help you recover from the noise, even if your home is already quiet, have an easy snack available when you get home, and arrange to have all high priority tasks for the day finished before you go out to socialize, so you don’t need to do any mental heavy-lifting or planning before you go to sleep.

-Another possibility is to look for activities or events that you’d like to do with your friends, and ask them if they’d like to go with you. You can intentionally choose activities and places that are less overwhelming. If they want to do these things with you, great! And if they don’t want to, that’s fine too. The point isn’t to immediately make a large change in their behavior, it’s to see if they’re interested, and take the pathway if it appears.

-Another thing you can do is gradually seek different friends, spaces, and communities that are a good fit for you. You don’t need to drop your existing friend group to do this. You can just go out and do other activities on your own and see if you connect with the people there. You might find it’s easier to socialize with people when you’re in an environment that’s not loud, crowded, and overwhelming. And, since you already have a friend group you can fall back on, you don’t need to feel desperate when talking to others/ seeking connection, as that can be a turn off. Over time, you may be able to build different circles of friends with different interests and social activities, so when you want social time you can choose which group of people and activities to turn to. By keeping yourself spending time with each group at least occasionally, you can maintain the social connections and stay friends. People have busy lives, so you don’t need be pressured to hang out with your friends each time they hang out. Center your social life around your legitimate needs, not around the social life society thinks you should perform.

tldr: Ear plugs, hat/sunglasses for sensory needs, take breaks, evaluate your overwhelm level throughout the evening, plan when to leave ahead of time depending of overwhelm level, leave before you are having a bad time. Recognize that your social battery and ability to deal with overwhelming surroundings vary based on other circumstances in your life; factor these things in when you make social plans. Be aware of peer pressure- humor is a good way to deflect it while still staying friendly, and good friends will respect your boundaries. Plan recovery time and activities after socializing and being in stimulating circumstances. Suggest sensory friendly activities to your friends, but no need to panic if they don’t want to do those things. Try finding sensory friendly activities and friends in addition to your existing friends and activities. Socialize based on meeting your actual social needs (not the social needs society expects you to have) and maintain social connection in groups you want to stay with.

Good luck!