Parties to the Convention have agreed to submit to the Conference of the Parties (COP) national reports on implementation of the Convention to inform on the implementation of activities relating to mitigation. The required contents and level of details of national reports and/or the timetable for their submission are different for developed and developing country Parties. This is in accordance with the principle of "common but differentiated responsibilities" enshrined in the Convention.

The Cancun Agreements enhanced existing provisions for reporting by requiring Parties to submit their national communications every four years. Additionally, developed countries should submit biennial reports and developing countries biennial update reports. Least developed countries and small island developing states will have flexibility to submit this information. Parties have also agreed to conduct "international assessment and review" (IAR) applicable to information submitted by developed country Parties; and international consultation and analysis (ICA) for information submitted by developing country Parties.

Developed countries are required to submit information on their national greenhouse gas (GHG) inventories annually. They also submit national communications periodically, according to dates set by the COP. The sixth national communications from these countries is due by 1 January 2014. From then onwards, they will be required to submit their national communications every four year. Developed countries that have ratified the Kyoto Protocol must include supplementary information in their national communications and annual national GHG inventories to demonstrate compliance with their commitments under the Protocol. Similarly, developed country Parties shall submit their first biennial reports by 1 January 2014 and their second and subsequent biennial reports two years thereafter.

Developing country Parties are also required to submit national communications which include a national GHG inventory. Until COP 16, there were no fixed dates for the submission of national communications from these countries, although these reports were to be submitted within four years of the initial disbursement of financial resources to assist them in preparing their national communications. At COP16, it was decided that developing countries would submit their national communications every four years. It was also decided that developing countries, consistent with their capabilities and the level of support provided for reporting, should submit biennial update reports containing updates of national greenhouse gas inventories, including a national inventory report and information on mitigation actions, needs and support received. At COP17, it was decided that developing countries should submit their first biennial update reports by December 2014 and the subsequent ones every two thereafter. The least developed country Parties and small island developing States may submit biennial update reports at their discretion.

REDD-plus forest reference emission levels and/or forest reference levels can also be submitted on a voluntary basis by developing country Parties. These submissions will be made available on the REDD Web Platform.