ASEAN is the Association of Southeast Asian Nations. Its main focus is on trade and development, though it also functions as a political force when the diverse nations involved agree well enough to issue joint statements. It includes a rather significant group of countries; total population is over 600 million and annual GDP over $3.5 trillion.
Travellers may need to be aware of the effects on visas; it is often easier for ASEAN citizens to get visas for other ASEAN countries than for outsiders, and agreements are in place with nearby nations such as China which affect visas in either direction. Creating a common ASEAN travel area, similar to the Schengen Agreement for Europe, has been suggested but, as of early 2014, no such arrangement is in place.
Another thing that affects many travellers is the ASEAN Single Aviation Market policy. This is a gradual process of opening up the markets which began in 2008, is now well along, and is expected to be complete by 2015. See Low-cost airlines in Asia for some of the effects.
Business travellers may be greatly affected by tariff reductions and other economic measures. The goal, expected to be reached by 2015, is an ASEAN Economic Community similar in concept to the European Economic Community with zero internal tariffs, common import duties, and a common policy in trade negotiations.
As of early 2014, the members are:
Currently, Papua New Guinea and East Timor have observer status; both seem likely to eventually become full members. Granting observer status to Bangladesh and Fiji has been proposed but not yet agreed on.
ASEAN also interacts with other nations. There are regular meetings for "ASEAN+3" (the ASEAN nations plus China, Japan and South Korea) and for a 27-member "ASEAN Regional Forum", and sometimes bilateral talks between ASEAN and various other countries.