Asias longest-serving elected leader arrives Monday on the eve of a two-day Association of Southeast Asian Nations summit, keeping a tight schedule even during his swansong, scheduling bilateral talks with leaders from China, South Korea, Myanmar, Vietnam and Indonesia.
ASEAN Secretary General Ong Keng Yong said the region would lose a "strong, colorful personality" when Mahathir, 77, steps down as premier on Oct. 31 after 22 years in power.
"The leaders want to acknowledge his contribution to ASEAN cooperation and cohesion, and bid him bon voyage," Ong told AFP.
"His legacy is his forthright analysis of situations, calling a spade a spade and always coming up with bold ideas. He speaks his mind and he has been proven right on many occasions.
"The feeling in ASEAN is that a strong colorful personality like Dr. Mahathir and his style will be missed," Ong added.
Summit host Indonesian President Megawati Sukarnoputri will deliver a tribute and present a memento a photograph of ASEAN leaders signed by all of them to Mahathir at the start of the summit Tuesday, officials say.
With the exception of Bruneis Sultan Hassanal Bolkiah who succeeded his father in 1967, Mahathir is the longest serving leader in the regional grouping founded in 1967.
He is the last of ASEANs old guard, who included Ferdinand Marcos of the Philippines, Indonesias Suharto and Singapores Lee Kuan Yew. Marcos was driven into exile in the US and died in 1989 and Suharto stepped down under popular pressure in 1998.
Singapores founding father Lee has become a senior minister since handing over the premiership to Goh Chok Tong in 1990.
Mahathir will hand over to his deputy Abdullah Ahmad Badawi after hosting the Organization of the Islamic Conference summit in Kuala Lumpur and going on to Bangkok, Thailand for his international swansong at the Asia-Pacific Economic Cooperation summit.
The doctor-turned-politician has been a trenchant critic of the West.
He ignored western pressure and let military-ruled Myanmar into the ASEAN fold during Malaysias chairmanship in 1997.
Mahathir has, however, made clear his unhappiness with the generals latest crackdown. He told AFP in July that Myanmar might one day have to be expelled from ASEAN but only as a last resort.