One of the best gadgets for travelers may already be in your pocket. From first researching a trip to remembering where you went once you get back, here are 30 ways to put your smartphone to use when you travel.
1. As a travel agent: If you know your destination but not your dates, use the Fly.com Custom Fare Calendars to search for the cheapest dates to fly specific routes. If you know your dates but not your destination, download the Today's Best Fares app to search for the cheapest flights from your city.
2. As a personal assistant: Keep your flight bookings, theater tickets, and restaurant reservations organized in one place with apps like TripCase and TripIt, which can also alert you to flight delays and better seat openings on your flight.
3. As a group planner: Download the Google Docs app or Evernote and share with your travel companions so that everyone can add their itineraries and recommendations in one easily accessible place. Glympse and Find My Friends can be used to temporarily share each other's locations so you can track arrival times and coordinate meeting spots.
4. As a last-minute packing assistant: Apps like Packing Pro generate suggested packing lists based on your destination and purpose, or create your own in Notes to check off before heading out the door.
5. As a map: As long as location services are enabled, you can see where you are on Google Maps even without a Wi-Fi connection or data (though not directions to where you want to go). For a more detailed map, download the offline version ahead of time from Google Maps, or use other apps like Maps.me (which has a search function) and Spyglass (specializing in outdoor navigation). I also make use of old-fashioned screenshots when I know I can't count on a continuous Wi-Fi connection (great for showing to cab drivers when there's a language barrier).
6. As a subway navigator: Most public transportation systems have an app to help you plan your route, even when you're offline. Examples include Embark for major U.S. cities and MVV Companion for Munich, which you can even purchase your tickets through.
7. As a Wi-Fi finder: The JiWire Wi-Fi Finder app can help you find free Wi-Fi wherever you are, even when you're offline.
8. As a hot spot: In a pinch, you can use your smartphone's data connection to create a Wi-Fi hot spot for other devices. However, this option burns through a lot of data, so use it wisely.
9. As a long-layover lifesaver: GateGuru is good for helping you navigate airports, and shows what restaurants and shops are in your terminal so you can avoid aimless wandering. If you get stuck due to a delay, plenty of mobile games can help you pass time (my favorite is Threes).
10. As a compass: Don't waste time wandering; use your phone's compass to get pointed in the right direction (built into iPhones or available as an app elsewhere).
11. As a flashlight: The flashlight function is another built-in feature that may come in handy in more remote corners of the globe, or even just going to the bathroom in the middle of the night when you can't remember where the lightswitches are.
12. As a translator: Study a language before your trip with the free Duolingo app, and supplement your knowledge with translation apps like Google Translate, which lets you type in words or hold the app over printed text to see an instant translation.
13. As a money saver: Use the Travelzoo app to search for deals at top-rated restaurants, shows, and hotels around the world.
14. As a phone: Hold the presses--yes, your phone can be used as a phone. However, it's important to know your options before racking up long-distance charges. My suggestion for shorter trips is to keep your cellular data turned off and use a Wi-Fi connection to make free long-distance calls through services like Skype and FaceTime. For longer trips where you need to stay in touch regularly, investigate other options, like purchasing a local SIM card.
15. As a currency converter: I recommend XE Currency App for its simplicity and ability to work offline (at the most recently downloaded exchange rate).
16. As a security system: Connect with the Department of State's Smart Traveler app to get travel alerts and warnings, U.S. embassy locations and more. The !Emergency! app supplies emergency-services phone numbers for wherever you are, and will automatically dial them for you.
17. As a first aid guide: Hopefully you'll never need it, but the Red Cross First Aid app lets you quickly access information to handle common first aid emergencies.
18. As a medical ID: You can add emergency info to your phone's lock screen, such as medications, blood type and emergency contacts.
19. As a scanner and filing cabinet: Business travelers can avoid overflowing briefcases with apps like Docs To Go, which lets you view and edit Microsoft Office documents on your phone. The free CamScanner app lets you use your smartphone camera as a rudimentary scanner, then email the document in whatever file format you want.
22. As a jet lag alleviator: Plug in your old and new time zones and the Entrain app calculates the best lighting schedule to help you adjust to your new time zone as quickly as possible.
23. As a camera: Your smartphone has likely already replaced your digital camera for everyday use, but a number of photography apps can take your smartphone photos to the next level with digital zooming, composition guides and editing tools.
24. As a luggage tracker: Devices like the LugLoc can help you locate your luggage with the tap of a smartphone, though they require an initial investment.
25. As a personal trainer: The Huffington Post lists five best fitness apps for travelers.
26. As a social coordinator: Smartphone travel apps like Tripr let you connect with locals as well as fellow travelers either ahead of time or once you're at your destination. Ship Mate is a social app specifically designed for cruise passengers.
27. As sleep insurance: For light sleepers, the SimplyNoise app is the best $0.99 you can spend. Pick between three frequencies of white noise to drown out sounds from paper-thin hotel walls or snoring travel companions. The Sleep Cycle power-nap app helps you time naps with your REM cycle so you can take the edge off jet lag without waking up groggy.
28. As a weather forecaster: Most smartphones can pull up a basic weather forecast with a single swipe. For more detailed information, weather apps can tell you whether the pollen count warrants packing allergy meds, when to time your beachside dinner reservation to catch the sunset, or when to have the best chance of spotting the northern lights.
29. As a personal driver: Skip the money exchange window--some car-service apps let you hail a car and pay with your phone. Hailo is available in many European and Southeast Asian cities, while Uber is currently in 65 countries.
30. As a memory preserver: If you've ever come home from vacation and found that all your photos of historic cathedrals are blurring together, SpeakingPhoto lets your narrate your photos as you go. Besides the classics like Instagram and Facebook, here are 15 other ways to digitally preserve your travels.
Kelsey Rexroat is an editor at Travelzoo and based in New York City. Travelzoo has 250 deal experts from around the world who rigorously research, evaluate and test thousands of deals to find those with true value.