Sandgate — Immediately adjacent to Clontarf along the foreshore path, Sandgate is the larger and better-served of the two bayside suburbs. It has a proper main street with cafés, restaurants, and a historic pier. Worth the short walk or cycle for a coffee or lunch if Clontarf's options fall short.
Shorncliffe — A short distance north along the foreshore, Shorncliffe has the Shorncliffe Pier — one of the longest timber jetties in Queensland — and a quiet, historic character. Easy to combine with a visit to Clontarf as part of a bay walk.
Bribie Island — About 45 minutes north of Brisbane by car, Bribie Island sits at the northern end of Moreton Bay. It is low-key and unhurried, with calm bay beaches good for families and a national park at the northern end. Accessible by road across the Bribie Island Bridge.
Moreton Island — A national park island accessible by ferry from Brisbane. The island has no paved roads, is home to wild dingoes, and offers good snorkelling, camping, and the famous Tangalooma wrecks (deliberately sunk to create an artificial reef for snorkelling). A full day minimum; camping is possible for longer stays.
Brisbane CBD — 30 to 40 minutes by train from Clontarf station. South Bank is the main cultural precinct, with the Queensland Art Gallery and Gallery of Modern Art (QAGOMA), the Queensland Museum, and the riverside parklands. Good for a half-day if you want more than the bayside suburbs offer.