HI All!

This will be our first time in Bar Harbor, Maine at the end of the summer (end of Aug/early Sep). We are considering AirBnB to save money (2 adults, 2 school age kids). Our kids really want to be able to swim during vacation. Will lakes/beaches be warm enough this time of year for swimming? (Not choosing a hotel means we don't get access to a hotel pool, unfortunately.)

Any "must stay in" areas for first time travelers to Bar Harbor?

It's never warm enough to go swimming in the ocean there, as far as I'm concerned. And I've been there, couldn't go in, and that was August.

info
https://www.currentresults.com/Ocean...emperature.php

You should expect water temps at most in the mid 60's close to the ocean, perhaps as high as 70 in a sheltered, shallow inlet. If that's "warm enough" for you then you're all set.

Personally I find mid 60's warm enough to go swimming as early as 4th of July, but then again I don't mind "refreshing" water. ymmv

https://acadiamagic.com/SandBeach.html

My husband will swim in very cold water. He went in a few years back at the end of August at Sand Beach (the beach in the National Park). He said it was the absolute coldest he has ever experienced.
This site indicates it rarely goes higher that 55 degrees. If the kids go in, it will certainly be refreshing!

Perhaps try Echo Lake:

https://acadiamagic.com/echo-lake.htm

perhaps the lakes. The ocean beach at the park is very beautiful but the water is never warm enough to really enjoy it. If you want to spend a night or two in southern Maine, the vast sandy beaches in Ogunquit, Wells, York, etc are considerably less frigid, and are great for cool water swimming.