There are a number of broad definitions of ‘the Indo-Pacific’ as a region:
“The Indo-Pacific comprises 40 countries and economies:
Australia, Bangladesh, Bhutan, Brunei, Cambodia, Democratic People’s Republic of Korea (DPRK), India, Indonesia, Japan, Laos, Malaysia, Maldives, Mongolia, Myanmar, Nepal, New Zealand, the Pacific Island Countries, Pakistan, People’s Republic of China (PRC), the Philippines, Republic of Korea (ROK), Singapore, Sri Lanka, Taiwan, Thailand, Timor Leste, and Vietnam.”
“…comprises the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the seas connecting the two.”
“In its widest sense, the term geopolitically covers all nations and islands surrounding either the Indian Ocean or the Pacific Ocean, encompassing mainland African and Asian nations who border these oceans, such as India and South Africa, Indian Ocean territories such as the Kerguelen Islands and Seychelles, Indonesia (which is within the bounds of both the Indian Ocean and the Pacific), Philippines, Taiwan, China, Korea, Japan, Russia and other Far East nations bordering the Pacific, Australia and all the Pacific Islands east of them, as well as Pacific nations of the Americas such as Canada or Mexico. ASEAN countries (defined as those in Southeast Asia) are considered to be geographically at the centre of the political Indo-Pacific.”