Maybe you don't always have enough time or energy to travel far around - taking also into account that public transport is not the fastest... So what to do on an unexpected free day or afternoon? But there's nice and interesting places around, too!
The first tip is obvious: Surely the salt lakes in Sovata will be the first thing to discover here, so I won't write a lot about this place. Besides they're easy to find: just follow all the tourists! It's good to know that the swimming area of Lacul Ursu, the largest one, is closed from 1 to 3 pm. If you don't want to pay the entrance of 30 lei, you can also swim in Lacul Mierlei. It's even more salty and quite muddy, but that's for your health ;) To have it more calm and quiet, especially in the busy summer season, it is very nice to visit the lakes in the evening. Or just wander a bit further on the narrow trails to the other small lakes, to the panorama tower or to the salt valley where there are small puddles with beautiful salt minerals (behind Lacul Mierlei).
It's a short funny trip to go with the tiny narrow-gauge steam train (Mocăniţa) from Sovata to Câmpu Cetăţii, one of the next villages, and back. Each direction takes about 1 hour. The train leaves from the small station/stop at Strada Gara mica (behind Penny), but only works in the summer months.
One more place nearby is all about salt: In the next village Praid there's not only a salt mine that's open for visitors, but also a salt canyon. There the small stream has cut its way through the upper part of a salt dome, so you can see it as white-grey rock surfaces. There's a very small entrance fee and the loop trail takes about 1 or 2 hours, depending on how closely you investigate those interesting structures and special scenery... To get there take one of the regular buses in direction to Odorheiu Secuiesc and walk 20 min from the center of Praid on Strada Minei.
Some kilometers further in the same direction lies the village Corund (hung. Korund) that is famous for its traditional pottery. So it's the place to buy a hand-made, regional and even practical souvenir if you like that rustic style. Of course you can also get any other more or less original and tasteful stuff from the many shops and stands along the village street.