The world map returns in Final Fantasy with Type-0, with players able to explore it as soon as Free Time 2.3 starts. Whenever you leave Akademeia, six hours will be removed from the remaining time you have left and if there's less than six remaining, then you will not be able to leave.
The overworld is split up into a bunch of different regions, with not all of them available for exploration at the beginning of the game, as they are under control of a different nation. As you do more story missions and other optional ones (Expert Trials), then more areas will become under Dominion control and you'll be able to explore them.
While exploring the overworld, you will get into random encounters, similar to older Final Fantasy titles. The battles play out like any other in the game, but there's a slight twist added to these ones. Sometimes upon completing a battle, you will get an option to either continue fighting or to retreat.
Choosing to fight will respawn the same set of enemies, but they will be a higher level. You will be able to continue fighting up to a total of five consecutive battles, after which, you will be sent back to the overworld map. You will also be sent back to the overworld upon choosing the retreat option.
Breakdown of Areas
The following is a breakdown of all of the areas in the game, along with any notable towns and/or dungeons that can be found in those areas.
|Northern Valley||--||Valley of Monsters|
|Old Lorica Region||--||Black Tortoise Crevasse, Blast Site|
|Jubanla Region||--||Northern Corridor (connects to North Togoreth), Mt. Jubanla (path on east side of volcano)|
|North Togoreth Region||Mi-Go||Northern Corridor (connects to Jubanla)|
|Meroe Region||Meroe||Bethnel Caverns|
|Iscah Region||Iscah, Rokol||--|
|Rilochy Province||Rilochy, Shakara||--|
|West Nesher District||Bazz||--|
|East Nesher District||--||--|
|Rubrum Region||Akademeia, McTighe, Aqvi, Corsi||Corsi Cave|
|Eibon Region||Toguagh||Tower of Agito (requires airship)|
|Roshana Province||Rama, Roshana||--|
|Veill Desolands||--||Silent Key|
|Innsmouth Region||--||Innsmouth Coast|
Note: You will need the Setzer airship in order to reach Northern Valley, Berith Desert and Dragon Sanctuary. All other areas are accessible via dungeons or on foot/chocobo.