ATM in townYes in principle: Ukunda (the town immediately behind the beach strip, pop. 77,686 in the 2019 census) is a real service town, not a village, and Diani Beach Shopping Centre on the beach road reportedly has a bank ATM. No bank-branch list for Ukunda itself is published, so check on the ground.
Nearest ATMUkunda town centre, ~2-4 km inland from the main Diani kite strip; full-service bank branches (ABSA, I&M, Bank of India confirmed in Mombasa's CBD) are a certainty only in Mombasa, ~36 km / 1-2 hrs away via the Likoni Ferry
BanksEquity Bank has a branch and ATM on Diani Beach Road, Ukunda (GPS -4.282242, 39.567622), and Equity Bank Kenya's own branch finder lists a 'Ukunda Branch ATM'. No street address is published for a second bank (KCB, Cooperative, GT Bank), so treat those three, reported as fee-free, as plausible only.
Cards acceptedKite schools, mid-range and upper hotels, and restaurants on the main tourist strip generally take Visa/Mastercard; small dukas, tuk-tuks, matatus, and beach vendors are cash (KES) or M-Pesa mobile money only
Where you need cashtuk-tuks and matatus · beach vendors and 'beach boys' · small dukas/kiosks · M-Pesa top-ups · tips for boat crew/guides