Kauaʻi has no club scene and does not pretend to: the evening is a luʻau, a beachfront bar with live Hawaiian music, or a brewery taproom, and nearly all of it is over by about 9:30pm.
Luʻau Kālamakū, Kilohana Plantation
3-2087 Kaumualiʻi Highway in Līhuʻe, on Tuesday and Thursday evenings plus selected Mondays in summer and winter. An imu ceremony unearths the pig, then an open-air staged show tells the voyage from Tahiti to Hawaiʻi with hula and fire dancers. Several package tiers; book ahead.
Smith Family Garden Luʻau, Wailua
Runs seven nights a week in the Wailua River valley, starting 5pm March–October and 4:45pm November–February. Lei greeting and a tram or walk round 30 acres of garden, imu ceremony at 6pm, open bar, then the Rhythm of Aloha show in a torch-lit amphitheatre at 8pm. Around $150 adults, $45 ages 7–13, $35 ages 3–6.
Duke's Barefoot Bar, Kālapakī Beach
3610 Rice Street in Līhuʻe, on the sand at Nawiliwili Bay, with live music every day. Open 11am–9:30pm Monday to Saturday and from 9am on Sunday, so "late" here means a sunset mai tai at the downstairs tiki bar rather than a night out.
Kauaʻi Island Brewing Company, Port Allen
4350 Waialo Road on the south-west coast, open 11am–9pm daily with happy hour 3–5pm and live music Tuesday to Sunday, 6–8pm. Ten-plus house beers, a full bar and a big lanai. Their second site in Koloa Village is a taproom and whiskey saloon with over 100 bottles.
Plan around the early close
Almost nothing on the island serves past about 9:30pm — Duke's stops at 9:30, the Port Allen brewery at 9 — and the drive between Hanalei and Poʻipū is over an hour on a single highway with no night traffic to speak of. If you want an evening out, eat early and stay near where you are drinking.