Okinawa Institute of Science and Technology Graduate University (OIST) is an interdisciplinary graduate school offering a 5-year Ph.D. program in Science. Over half of the faculty and students are recruited from outside Japan, and all education and research are conducted entirely in English.
OIST has a yearly internship program called OIST Research Internship Program. The program will take 2-6 months through a system of undergraduate and graduate placements as Research Interns. The interns will world under the direction of a Professor at OIST and contribute to the research activities of OIST. This internship program is awarded twice a year. While the application period is on months before.
If you are selected, you will get Living Allowance of 2,400 JPY per day (weekend excluded), commuting support (if necessary), and accommodation either on campus or nearby, visa acquisition, insurance, and local registration.
Furthermore, here is the schedule of the application and program start:

Explore more information about this internship here.