Flashing your cash sends a clear signal to any unsavory types lurking about. Keep limited amounts of cash on your person – always carefully concealed in a wallet or purse. And put your cash in two different places so if one stash is stolen you’ll have backup. Possible choices: your in-cabin safe (if you’re on a ship that provides them – check ahead of time), your waterproof zipped bag (mentioned above), a locked briefcase or suitcase, or inside your laptop, provided you can lock the case.
Use credit cards and charge services and items to your cabin when possible. And always travel with two credit/debit cards so you have a backup if one is lost, stolen, or its credit line is frozen.