Thailand will deploy almost 10,000 security personnel at Phuket to keep protesters away from a high-level regional meeting later this month.
Defence minister Prawit Wongsuwan said on Friday all rallies were banned until 24 July to prevent a repeat of the cancellation of an East Asia Summit, in April.
Ministers from the United States, European Union, China, Japan, Australia, Russia, New Zealand, India, South Korea, Canada will attend meetings with the 10 members of the Association of Southeast Asian Nations from 17-23 July.
Prawit admitted the government underestimated the determination of the protesters, who invaded the venue and prompted the evacuation of ASEAN leaders by helicopter. He said it would not happen again.
Emergency rule was declared in Bangkok for 12 days afterwards to quell street protests.
Phuket is an island, 860km south of Bangkok.