The Mentawai Islands Regency is a regency of West Sumatra Province which consists of a chain of about a hundred islands and islets approximately 150 kilometres (93 miles) off the western coast of Sumatra in Indonesia. They cover a land area of 6,033.76 km and had a population of 76,173 at the 2010 Census and 87,623 at the 2020 Census; the official estimate as of mid-2023 was 95,068.

Siberut at 3,877.9 square kilometres (1,497 square miles) is the largest of the islands, occupying 64.27% of the land area of the regency. The other major islands are Sipura (or Sipora), North Pagai (Pagai Utara), and South Pagai (Pagai Selatan). The islands lie off the Sumatran coast, across the Mentawai Strait. The indigenous inhabitants of the islands are known as the Mentawai people. The Mentawai Islands have become a noted destination for surfing, with over 40 boats offering surf charters to international guests.

The Mentawai Islands have been administered as a regency within the West Sumatra (Sumatera Barat) province since 1999. The regency seat is Tua Pejat, on the island of Sipora. Padang, the capital of the province, lies on the Sumatran mainland opposite Siberut. The regency is divided into ten districts (kecamatan), tabulated below from south to north with their areas and their populations at the 2010 Census and the 2020 Census, together with the official estimates as at mid-2023. The table also includes the locations of the district administrative centres, the number of villages (all classed as rural desa) and the number of named offshore islands in each district, and its postcode.

Name of District (kecamatan)	English Name	Area in km	Pop'n 2010 Census	Pop'n 2020 Census	Pop'n mid 2023 Estimate	Admin centre	No. of villages	No. of islands	Post code
Pagai Selatan	South Pagai	851.28	8,782	9,373	10,279	Bulasat	4	31	25391
Sikakap	Central Pagai	312.60	9,531	10,219	10,821	Taikako	3	8	25399
Pagai Utara	North Pagai	371.25	5,212	6,031	6,495	Saumanganya	3	9	25390
Sipora Selatan	South Sipora	348.33	8,460	9,812	10,552	Sioban	7	3	25392
Sipora Utara	North Sipora	272.40	9,097	11,968	13,405	Sido Makmur	6	12	25398
Siberut Selatan	South Siberut	328.00	8,446	9,933	10,711	Muara Siberut	5	1	25397
Siberut Barat Daya	Southwest Siberut	1,013.83	6,069	7,058	7,686	Pasakiat Taileleu	3	17	25393
Siberut Tengah	Central Siberut	589.75	6,069	7,089	7,716	Saibi Samukop	3	5	25396
Siberut Utara	North Siberut	782.68	7,774	8,337	9,151	Muara Sikabaluan	6	4	25395
Siberut Barat	West Siberut	1,163.64	6,733	7,803	8,252	Simalegi	3	1	25394
Totals		6,033.76	76,173	87,623	96,068	Tuapejat	43	111

Note: (a) Sikakap District covers the northern part of South Pagai Island and the southern part of North Pagai Island, plus some intervening small islands. Of the three desa, Matobek is entirely on North Pagai Island, while Sikakap and Taikato are mainly on North Pagai Island but each includes areas on South Pagai as well as the intervening small islands.

The ten districts comprise forty-three rural villages (desa) listed below with their areas and their populations as officially estimated for mid 2023:

Kode Wilayah	Name of desa	Area in km	Pop'n Estimate mid 2023
13.09.10.2001	Sinaka (Sinakak)	265.87	2,455
13.09.10.2002	Bulasat	224.00	2,703
13.09.10.2003	Malakopa (Malakopak)	127.63	2,745
13.09.10.2004	Makalo	233.78	2,376
13.09.10	Totals Pagai Selatan District	851.28	10,279
13.09.09.2001	Sikakap	35.82	5,226
13.09.09.2002	Taikako	168.20	3,510
13.09.09.2003	Matobe (Matobek)	108.59	2,085
13.09.09	Totals Sikakap District	312.60	10,821
13.09.01.2007	Betumonga	76.91	1,303
13.09.01.2008	Silabu	97.63	1,308
13.09.01.2009	Saumanganya	196.72	3,884
13.09.01	Totals Pagai Utara District	371.25	6,495
13.09.02.2001	Bosua	40.78	1,780
13.09.02.2002	Beriulou	78.93	1,081
13.09.02.2003	Nemnemleleu	46.91	1,377
13.09.02.2004	Mara	62.27	1,198
13.09.02.2006	Sioban	16.75	2,329
13.09.02.2007	Matobe	23.62	1,265
13.09.02.2008	Saureinu	79.47	1,522
13.09.02	Totals Sipora Selatan District	348.33	10,552
13.09.08.2001	Betumonga	110.58	1,339
13.09.08.2002	Goisooinan	56.07	1,226
13.09.08.2003	Tuapejat	86.52	6,404
13.09.08.2004	Sido Makmur	6.07	985
13.09.08.2005	Bukit Pamewa	7.72	850
13.09.08.2006	Sipora Jaya	5.44	2,601
13.09.08	Totals Sipora Utara District	272.40	13,405
13.09.03.2002	Muara Siberut	17.75	3,259
13.09.03.2003	Maileppet	18.77	1,833
13.09.03.2004	Muntei	90.94	1,798
13.09.03.2005	Matotonan	85.65	1,336
13.09.03.2007	Madobag	114.89	2,485
13.09.03	Totals Siberut Selatan District	328.00	10,711
13.09.06.2001	Katurei	128.35	2,406
13.09.06.2002	Sagulubbeg	469.47	1,676
13.09.06.2003	Pasakiat Taileleu	416.00	3,604
13.09.06	Totals Siberut Barat Daya District	1,013.83	7,686
13.09.07.2001	Saibi Samukop	230.63	3,692
13.09.07.2002	Cimpungan	93.84	1,223
13.09.07.2003	Saliguma	265.28	2,801
13.09.07	Totals Siberut Tengah District	589.75	7,716
13.09.04.2003	Bojakan	263.04	1,168
13.09.04.2004	Sotboyak	42.83	719
13.09.04.2005	Mongan Poula	30.61	1,085
13.09.04.2006	Muara Sikabaluan	43.41	2,638
13.09.04.2007	Sirilogui	107.24	1,369
13.09.04.2008	Malancan	295.55	2,172
13.09.04	Totals Siberut Utara District	782.68	9,151
13.09.05.2001	Simatalu Sipokak	309.47	3,642
13.09.05.2002	Simalegi	559.19	2,396
13.09.05.2003	Sigapokna	294.98	2,214
13.09.05	Totals Siberut Barat District	1,163.64	8,252

Macaronis was first discovered in 1980 by pioneer surf discoverers Chris Goodnow, Scott Wakefield, and Tony Fitzpatrick, who originally named the break ‘P-Land’ on their first visit (after Pasangan Bay / Pagai Islands). Amazingly, and considering the remote location, P-Land may have been the first wave surfed in the Mentawai Islands. Lances Right was discovered a full 10 years later, while Chris, Scott, and Tony continued to keep their discovery a secret. They returned in 1981 with friend Tim Annand, and again on a boat trip in the 90’s.

The first photos of the surf breaks in the Mentawais area were leaked after a surf trip in 1992 aboard the MV Indies Trader, with professional surfers Ross Clarke-Jones, Tom Carroll, and Martin Potter. Ever since then, the Mentawai Islands have been well on the radar of surf travellers around the world. At the West of Sumatra, the Mentawai Islands have the most consistent surf breaks in Indonesia making it one of the preferred choices for serious surfers. The tropical waters surrounding the islands offer year-round waves up to 15 ft (4.5 m).

The islands have been separated from Sumatra since the mid-Pleistocene period, which has allowed at least twenty endemic species to develop amongst its flora and fauna. This includes six endemic primates: the Kloss's gibbon (Hylobates klossii), Mentawai macaque (Macaca pagensis), Siberut macaque (Macaca siberu), Mentawai langur (Presbytis potenziani), Siberut langur (Presbytis siberu), and pig-tailed langur (Simias concolor). They are highly endangered due to logging, unsustainable hunting, and conversion of rainforest to palm oil plantations. Some areas of the Mentawai Islands rainforest ecoregion are protected, such as the Siberut National Park. Red junglefowl, the Asian palm civet, and crab-eating macaque are also native.

The Mentawai Islands lie above the Sunda megathrust, a seismically active zone responsible for many great earthquakes. This megathrust runs along the southwestern side of Sumatra island, forming the interface between the Eurasian Plate and the Indo-Australian Plate.

Earthquake and tsunami activity has been high since the 2004 Indian Ocean earthquake. In 1833, the region was hit with an earthquake, possibly similar in size to the 2004 Indian Ocean earthquake; another large earthquake struck in 1797. On October 25, 2010, an earthquake in southern Sumatra led to a deadly tsunami that devastated villages in South and North Pagai. On March 3, 2016, an earthquake of 7.8 magnitudes occurred off the Indian Ocean, a few hundred kilometres from Mentawai islands, as a result of strike-slip faulting within the oceanic lithosphere of the Indo-Australia plate.

• Mentawai ethnic group
• Mentawai Festival

• Official website
• Anthropology of the Mentawai Islands
• Native Planet: The Mentawai