As of March 2021, no longer restricted. Previously, foreign investment in some O&G services was limited to up to 49% equity holdings.
"APPENDIX III - REGULATION OF THE PRESIDENT OF THE REPUBLIC OF INDONESIA NUMBER 49 OF 2021 CONCERNING AMENDMENT TO PRESIDENTIAL REGULATION NUMBER 10 OF 2021 CONCERNING THE INVESTMENT BUSINESS SECTOR
LIST OF BUSINESS FIELDS WITH CERTAIN REQUIREMENTS
- Oil and gas construction services (spherical tank,  offshore pipeline installation), Oil and gas, geology and geophysical surveying services  [see 2019 restrictions below]: Open (without condition) [no longer listed].[...]"(Presidential Regulation (PERPRES) No. 49 of 2021 Concerning Amendments to Presidential Regulation Number 10 of 2021 concerning Investment Business Fields [google translation])
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Previously: up to 2020
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"APPENDIX III - REGULATION OF THE PRESIDENT OF THE REPUBLIC OF INDONESIA NUMBER 44 YEAR 2016 CONCERNING LISTS OF BUSINESS FIELDS THAT ARE CLOSED TO AND BUSINESS FIELDS THAT ARE OPEN WITH CONDITION TO INVESTMENT - 
LIST OF BUSINESS FIELDS THAT ARE OPEN UNDER SPECIFIC CONDITIONS [...]
D. Energy and Mineral Resources Sector
-Business Field : Oil and gas construction services (spherical tank,  offshore pipeline installation), Oil and gas, geology and geophysical surveying services: Foreign capital ownership: Max.49% [...]"(PRESIDENTIAL REGULATION OF THE REPUBLIC OF INDONESIA NUMBER 44 YEAR 2016 CONCERNING LISTS OF BUSINESS FIELDS THAT ARE CLOSED TO AND BUSINESS FIELDS THAT ARE OPEN WITH CONDITIONS TO INVESTMENT)
Presidential Regulation (PERPRES) No. 49 of 2021 Concerning Amendments to Presidential Regulation Number 10 of 2021 concerning Investment Business Fields [google translation]
PRESIDENTIAL REGULATION OF THE REPUBLIC OF INDONESIA NUMBER 44 YEAR 2016 CONCERNING LISTS OF BUSINESS FIELDS THAT ARE CLOSED TO AND BUSINESS FIELDS THAT ARE OPEN WITH CONDITIONS TO INVESTMENT
[<a href="https://peraturan.bpk.go.id/Home/Details/168534/perpres-no-49-tahun-2021">PR49</a>],[<a href="https://peraturan.bpk.go.id/Home/Details/161806/perpres-no-10-tahun-2021">PR10</a>],[<a href="https://peraturan.bpk.go.id/Home/Details/40374/perpres-no-44-tahun-2016">PR44</a>]