If you're looking for anime similar to Azur Lane: The Animation - Aoki Kouro ni Vacances wo, you might like these titles.
In present day Japan, during what should have been a routine training exercise, Captain Umeza and the battleship Mirai are suddenly hit by a storm, sending them back in time to the middle of World War 2. Armed with state-of-the-art technology, the Mirai could alter the course of history; but for its crew, the situation presents a moral dilemma: do they have the right to meddle with history, even to stop the most dreadful tragedies of the war, when even the smallest acts could have unforeseen consequences?
Akeno Misaki and Moeka China share one goal—to join the Blue Mermaids! A group of fierce women, the Blue Mermaids are key to keeping peace among the seas and coastal cities in this age of maritime trade. To be a part of this elite group of sea protectors, they must succeed at Yokosuka's Marine High School. Akeno and Moeka, together with their classmates, will take the plunge to become Mermaids!
The crew of the Harukaze relax after midterm exams, and a Coco receives a new mission.