If you're looking for manga similar to The Prince and the Coral Sea, you might like these titles.
The forests are in danger! Tina and Tai stumble upon a space pod that has crash-landed onto earth! Befriended by two space aliens, they are unwittingly dragged along on a recovery mission that takes them deep into the forests around the world. However, the kids soon discover that the forests are disappearing! What is going on?! Can they learn the science behind the forests' disappearance and do something before it’s too late?!
April 1945, Okinawa. While Japan has been at war for some time now, the small tropical island of Japan still seems untouched by conflict. It is there that little Tomiko lives in joy and good humor, despite the absence of her mother. However, when the bombing begins and her father has to go to the warfront, her daily life changes. Now, she will have to survive... survive against all odds!!
Ryukyu (ancient Okinawa) is in its golden era in 1482. A young girl named Yuna is shunned by her community because she has the ability to talk and see spirits. Her only friends are a pair of stone lions named Shi and Sa. One day the rumour of Yuna’s god-given gifts reaches the King’s ears. Sho Shin travels to meet Yuna in disguise, kicking off their strange adventure…
3/11... As a result of the biggest earthquake disaster in history, everything changed that day. It has now been 50 years since the Great East Japan Earthquake hit Japan. The Earth has finally run out of oil, and society is undergoing a huge shift as it migrates away from its dependence on fossil fuels. People now get their electricity from solar and wind, and use as little of they're able to produce as possible - meaning a life without automobiles or flashy neon signs. An elderly person who lives on the coast where a nuclear power plant once was became resentful upon recalling how well-off Japan was at the time... until being moved to tears after noticing the beautiful star-filled sky that never could have been seen back then.
I, Teruaki Nakamura, transferred to a school Okinawa and developed a crush on a girl named Kiyan-san, but I don't understand her dialect. Higa-san is always helping me by translating the dialect. A slightly different cultural love starts on the southern island.