The Social Security Agreement between the UK and Japan signed in Tokyo on 29 February 2000 came into effect on 1 February 2001. The purpose of this Agreement is to prevent workers seconded from the UK to Japan (and vice versa) contributing to social security pension schemes in both countries at the same time. The Agreement provides that when a worker is sent on detachment from one country to the other, he and his employer remain liable to contribute only to the "home" country's pension scheme. The "period of detachment" is limited to a maximum of five years, although in exceptional circumstances this may be extended up to another three years.

Copies of the agreement can be viewed at the UK Office of Public Sector Information website