I travel solo frequently which means leaving stuff on the beach if I want a swim, so I take just enough cash to last the day, cheap phone, decent earphones (!) and a debit card with next to sod all on it (top it up daily via the bank's app); everything else left in the hotel room safe (probably the most unsafe place, but at least insured!) and use one of those straps you can swim with - so if they nick my bag and take my dinner that's all they get; although there's the prospect of them disappearing and leaving me without any clothes at all!!