Japanese space weather research and operation began in 1896 with research on radio propagation. LF, MF, and HF radio communication used to be important before the era of communication satellites; however, they are affected by ionospheric conditions and solar activity. A center for the research and development of radio systems was established at Hiraiso, which is now also a space weather observatory for measuring solar activity, geomagnetic fields, and ionospheric conditions. The need for space weather information initially decreased in the communication satellite age, but since the beginning of the 21st century it has been increasing again with the growing use of positioning satellite systems. The role of Southeast Asian countries in space weather research has become important and the range of activities is also growing. The contribution of these countries to space weather research and operation is expected to grow in future.