As a service to the many other people that will travel in Europe after me, I thought I would compile a list of the most important apps I used. Organized from most used to least used, these apps were crucial to travel planning and communication with family and friends.
1. Rail Planner Eurail/Interrail (Works Offline)
Hands down the #1 app I used the most was the Eurail app. It was vital to figuring out train schedules from the Netherlands to Croatia. I was the savior more times than I can count, when we would be transferring trains in a small town, I could see the other travelers, and I could see they didn't know which train they were supposed to transfer to, and thanks to this app, I was able to guide everyone. Best of all, this app works offline. NOTE: The DB Navigator is also a great rail planning app to utilize, but it only works with an internet connection.
Whenever we needed to weigh the options of how to travel, Rome2Rio was the first place we would go. It made any travel logistics a breeze. We used it extensively in parts of southern and central Europe when train travel wasn't a realistic option anymore and we needed to use bus travel more often.
This app makes it so easy to communicate with family and friends back home as it acts like a VOIP phone, or a phone/text message service you use over WiFi. Numerous times, my parents would comments that they felt like I was right there with them, and not in a small Bulgarian town when we were speaking over WiFi. So many apartments, hotels, pensions, and cafes offer wifi, that you will rarely ever feel off the grid. The silent hero in this whole thing was that we used this app many times to coordinate meetups with our AirBNB apartment hosts, and with friends we made while traveling.
4. Maps.Me (works offline)
Before we entered a new country I would do two things. #1 - Write down key phrases of the new language onto a single sheet of paper, we would use as a cheat sheet. #2 - Download the new country map from Maps.Me. Combined with GPS and offline mode, this map app helped us out so many times! Before we left one city, we would pin the train station, and our new place on the map in the city we were traveling to. We felt lost plenty, but we were really lost never. The best inadvertent gift at the end of our trip was that we had already pinned everywhere we went out of necessity, now we can use that map as a great memory! NOTE: Google Maps also has ways to download map sections for use offline.
5. Google Translate (works offline)
The instant text translation feature that uses the smartphone camera was always useful, especially for pointing at menus in other languages. It wasn't perfect, but it gave you enough to go on. For instance, you might not get all the ingredients in a menu but enough to know you are looking at some sort of fish soup. Serve it up!
Other Notable Apps
AirBNB - If you are traveling as a couple, it's possible to stay cheap at a place with your own kitchen and bathroom.
Booking.com - This is another very good solution to find small hotels, apartments, and pensions. We split our four months in thirds with AirBNB, Booking.com, and bigger hotels.
PrivateInternetAccess - This can be a good VPN solution for extra security when you are connecting to so many WiFi hotspots.
Snapseed - This app has great photo editing tools to take your camera phone photos to a different level.