Marvel Cinematic Universe has kicked off Phase 3 with a bang, and with its upcoming movies, it looks like it won’t be stopping. There is already a thick air of anticipation for the release of Thor: Ragnarok, Spider-Man: Homecoming and especially for the last two films of Phase 3, Avengers: Ragnarok. Marvel has not yet given any indications about their plans for Phase 4 as they did with the current one but it looks like the expansion will be much closer to Earth than outer space.
The social media site Reel News Hawaii recently posted that Aquaman, as well as Submariner, will be shooting in Hawaii. The news about Aquaman should not be surprising, given that the shooting for the upcoming DCEU film has been stated in the press. Submariner, however, has not been talked about, not even mentioned by the MCU in passing. Reel News was responsible for the Inhumans leak, so their word should have some credit and not be just anther speculation.
Namor The Submariner was one of the oldest superheroes in the Marvel Universe. Dating back to the time when Marvel was still called Timely Comics. Namor is the son of a human sea captain and an Atlantean princess. He is also the Prince of Atlantis who does not really trust land dwellers but has joined groups such as the Invaders, the Defenders, and the X-Men. His super powers include super strength, endurance, and flight (he has small wings on his ankles).
Since Marvel has yet to confirm that Namor will be included in Phase 4, fans should also not have too high of a hope. But Kevin Feige had stated that Marvel Cinematic Universe Phase 4 would focus more on characters than just the multiverses. Maybe this was his way of indirectly telling fans that the deep sea was the next part of Marvel.