For decades the main tool used to gain insight into sea turtle distribution and migration was flipper tagging. This has been a vital tool in discovering information that before was completely unknown, but there have been recent technical advancements allowing the use of satellite transmitters to track sea turtles. This has greatly increased the knowledge we have today of marine turtle migrations.
These transmitters work like a radio, transmitting a signal that can be detected by orbiting satellites. This allows us to track marine turtles, not only when they are surfacing, but also when below the surface, this technology holds great potential for discovering and understanding more about marine turtle behavior and ecology.
If you want to get involved yourself some countries, like the British Virgin Islands, allow tourists to flipper tag turtles. Here is a manual on the proper way to attach a flipper tag.