I ordered some suits from Vitamin A Swim and love them!! They try to be as sustainable as possible and have a bunch of cute options. Also! Im not affiliated with the company or anything but I can refer you as a friend and you get $25 off. Feel free to DM me if you end up ordering anything.
I bought a Vitamin A suit two years ago and have loved it. I feel their sizing is pretty true to size. I’ve also loved suits I’ve gotten from L*Space, which is sold in boutiques and stores like Nordstrom all over the country. I know they have a sustainable line, and I’m fairly certain they’re made in the US. Beyond that, I buy from Poshmark. You’ll find lots of brands with familiar sizing (maybe you know exactly what size you are in J Crew, etc) and buying second hand is not only soooo much more affordable (I just bought a NWT Vitamin A bikini top for $33 that is still available online for $118) but it’s often more sustainable too.
Cupshe has some cute options in several different styles with varying levels of coverage. I personally don’t like the cheeky look and prefer high waisted bottoms. Plus it’s reasonably priced, they usually also have sales or promo codes available.
The dreaded bathing suit buying experience....I love Athleta's swimwear. I own about 4 of their suits. They have a very generous return policy and the dye lots from season to season are consistent. So if you need to replace or add a piece they coordinate well with your existing suits. Good price points as well. Good Luck!
My mom is a big Lands End swimsuit fan. I have never tried them, but she was always really happy with the suits she got from there. I would order them for her and they seemed to have a really good selection of styles and fabrics. This is the year I am going to give them a try.
My favorite swimsuits recently have come from Everything but Water. (Looks like there are a couple in the Denver area.) They are pretty expensive but hold up well for a long time. And bathing suit shopping is not something I'm rushing to repeat so it's worth it!
Target is absolutely my favorite place to buy swimsuits. I think the quality and selection have greatly improved in the past 3-4 years. In addition to the latest trends, they also have a good variety of styles for various preferences, such as active swimwear or suits that are more modest/offer sun protection. Dressing rooms may be closed in some stores due to COVID, but in that case you can always try stuff on at home and return anything that doesn't fit.
My favorite brand with exact bra size is for sure Panache I got at Petticoat Fair, that bathing suit lasted me 4 summers and was totally worth the investment. For just a regular S,M,L ect.. bathing suit I have had luck with the Cocoship brand on amazon very retro quality fabric bathing suits. Then I have lucked out at target a couple times over the years and also H&M if your looking for a more trendy suit.