More than a million Australians will sail out of local ports this summer, and a good chunk of them are headed for the South Pacific. Carnival, Royal Caribbean, Celebrity and Princess are all running island itineraries — but cruise lines have issued a blunt reminder before anyone steps ashore: what you wear in port matters.

Many of the island communities that welcome cruise ships, particularly in New Caledonia and neighbouring nations, are religiously conservative. That means clothing norms are stricter than on the pool deck. G-strings, speedos and walking through town in nothing but swimmers are seen as disrespectful, and locals have had enough. The small island of Lifou, which will host Carnival, Celebrity and Princess ships this season, has become the focus of the warning. One Cruise Passenger reader reported seeing passengers come ashore without covering up, calling it rude and warning it could "ruin it for everyone" — and there are real fears ports could stop accepting cruise visitors altogether.

That's a different dynamic to overtourism complaints in places like Europe or Alaska, where the gripe is sheer volume rather than behaviour. In the South Pacific, it's the conduct of passengers themselves on the line, and both cruise lines and local communities want better communication and enforcement this season.

The practical fix is easy. Aim for the "knee and shoulder" rule when you're off the beach: cover both whenever you're walking around town. Sarongs, light flowy dresses, linen shirts and cover-ups all do the job in the heat, and two sarongs — one at the waist, one over the shoulders — is a tidy combo. Choose fuller-coverage swimwear, and put proper clothes on when moving between places rather than strolling through town in a bikini. Forgot to pack? Local markets usually sell sarongs, so grab one at the port before exploring. And pay attention to headwear customs: in Fiji, for example, hats are traditionally the village chief's prerogative, so take yours off in a village setting.

It's not just the Pacific, either. European towns are cracking down on beachwear in the streets — Varenna on Lake Como bans bare chests and swimwear outside beach areas on pain of €50–200 fines, Sorrento's rules run to €500, and Croatia warns of fines for shirtless tourists in signed zones. Sacred sites are stricter still: the Vatican rejects shorts above the knee and sleeveless tops, Bangkok's Grand Palace bans cropped or transparent clothing, and Abu Dhabi's Sheikh Zayed Grand Mosque asks women for loose ankle-length clothing, sleeves to the wrists and hair coverage.

The takeaway for anyone cruising this summer: read the port notices your cruise line sends instead of skimming them, and ask a crew member if anything's unclear. Pack a lightweight shirt, suitable trousers or skirt and a scarf in your shore bag — a beach morning and a village or temple visit can demand very different outfits. A little effort keeps the welcome mat out, both for you and for every cruiser who sails after you.