A subsidiary of the mining and commodities trading giant Glencore has pleaded guilty to seven counts of bribery in a London court.
The firm also said it will pay more than $1bn (£800m) to resolve similar claims with the US and Brazil.
The UK's Serious Fraud Office said it had exposed "profit-driven bribery and corruption" across Glencore Energy UK's oil operations in five African nations.
The firm will find how much it must pay in fines at a sentencing in June.
It previously set aside $1.5bn to cover the investigations it faced in the UK, US and Brazil.
Glencore's chairman said "unacceptable practices" had taken place in relation to the bribery charges it pleaded guilty to at Westminster Magistrates' Court on Tuesday.
The company's agents and employees paid bribes worth over $25m for preferential access to oil, with approval by the company between 2011 and 2016, the Serious Fraud Office (SFO) said.
The bribes were paid in Cameroon, Equatorial Guinea, Ivory Coast, Nigeria, and South Sudan, it added.