SEALION is an ionospheric observation network in Southeast Asia. It has been conducted by NICT since 2003 in aiming to monitor equatorial ionospheric disturbances, especially plasma bubble that poses a big impact on radio waves. SEALION is one of few observation bases in the world that is unique in having the conjugate observational points in the northern and southern hemispheres and around the magnetic equator.

SEALION is operated with an international effort by King Mongkut's Institute of Technology Ladkrabang (KMITL), Chiang Mai University (CMU), National Institute of Aeronautics and Space of Indonesia (LAPAN), Institute of Geophysics, Vietnam Academy of Science and Technology (IGP-VAST), University of San Carlos (USC), Kyoto University, Rajamangala University of Technology Isan (RMUTI), National University of Laos (NUOL), and Geo-Informatics and Space Technology Development Agency (GISTDA).

In January 2020, a new VHF radar was installed in Chumphon, Thailand. Chumphon is close to the magnetic equator, where plasma bubbles tend to be generated. The whole picture of plasma bubble generation is expected to be precisely captured by the radar.