So you can whip together a weekend bag or fit a fortnight’s worth of outfits into a rolling suitcase, but does your status as “packing guru” extend to your phone or tablet? Think of your device as a second carry-on, with its own packing list of apps that are essential for entertainment, getting around, safety and more.

“Everyone talks about making the super app, the one place for everything you need,” said Gilbert Ott, partnerships director at Point.me,a website that helps travelers manage loyalty points, “but no one has done it yet.” Until that super travel app exists, here are some suggested apps to download before you go.

Safety and security

Public Wi-Fi networks like those in cafes and hotels may not be secure, so to keep criminals from intercepting passwords, credit card numbers and emails, “it’s better to encrypt your internet activity,” said Mr. Ott. One method to keep data secure is to download and use virtual private networks like NordVPN or ExpressVPN, which encrypt your web doings. Both charge about $13 per month for a monthly plan, and about half that rate for a yearly plan. Another VPN provider, Mullvad, charges about $5.50 per month.

It may be tempting to store copies of important documents like passports, health insurance cards and prescriptions on your phone as photos, but it’s more secure to use apps that encrypt that information, like 1Password (starting at $35.88 per year) and Microsoft OneDrive Personal Vault (included with a $99.99-per-year Microsoft 365 subscription or, for nonsubscribers, three files free storage).

Getting around

The U.S. government’s free Mobile Passport Control app can help U.S. citizens and some other groups — even travelers not in the Global Entry program — make their way through immigration and customs more quickly by scanning their passport into the app and adding a selfie within four hours of arrival. Preloading the information speeds your interaction with the officer.

For detailed information on public transportation that can go beyond Google Maps, Moovit (free with ads or Moovit+ with additional features and no ads for $17.99 per year) and Citymapper (free with ads or $9.99 per year) can help with routes, fares and trip length around the world. In cities like New York and London, make sure you’ve loaded a credit or debit card in your digital wallet and set it up for transit to avoid lines by using touchless payment at turnstiles.