In recent months Thai Prime Minister Srettha Thavisin has been discussing the proposal with his counterparts as part of efforts to attract long-haul travelers and boost tourism, Bloomberg reported.
The joint visa would enable tourists to explore all six Southeast Asian countries on a single visa, the Bangkok Post reported.
A Schengen visa allows holders to travel in 27 member-countries for a maximum of 90 days.
Last year the six Southeast Asian nations welcomed a combined 70 million foreign tourists, according to official data.
Malaysia and Thailand, who waived visas for Chinese and Indian tourists, received the highest numbers.