Ringed by mountains, Tazawa-ko's lovely sandy beach, Shirahama (白浜), might actually be Japan's best swimming beach outside the remote islands, but only in the warmest months. Rent pleasure-craft at the nearby boathouse from spring to autumn. Romantic sunset strolls are highly recommended any time of year: on the lake's eastern shore, you'll find Tazawa-ko's famed bronze statue of the legendary beauty Tatsuko, sculpted by Funakoshi Yasutake.
A 20km road wraps around the lake, perfect for a slow drive or vigorous cycle – bike rentals are available in the small village of Tazawa Kohan (¥400 per hour). Sightseeing buses depart Tazawa-ko Station and loop around the lake, stopping for 15 minutes to admire the statue of Tatsuko.