The Japanese government is reportedly considering mandating operators not to sell SIM-locked handsets to make it easier for users to switch providers.
Japan's Internal Affairs and Communications Ministry is working on such a policy and could present the completed details by the end of the financial year ending in March 2015, sources told the Japan Times.
The proposed policy is said to be aimed at reducing the cost of mobile services, improving freedom of choice for Japanese consumers and promoting the use of MVNOs.
Japanese operators often sell SIM-locked phones with significant subsidies on postpaid contracts, but some mobile users have been complaining about the expensive monthly rates used to pay for the subsidies.
The ministry introduced guidelines calling for the removal SIM locks in 2010, but as the guidelines were voluntary they had little effect.
Terrie Loyd from AkihabaraNews notes that foreign travellers now have to buy a whole phone to use Japanese networks, but if the prohibition on SIM-locking takes effect, they will only have to purchase a SIM.