[14] In 2005, the company's Discoverer Spirit rig set a world record for the deepest offshore oil and gas well of 34,189 ft (10,421 m).

[15] In 2007, the US Department of Justice and the Securities and Exchange Commission filed a case against Transocean, alleging violations of the Foreign Corrupt Practices Act.

The case alleged that Transocean paid bribes through its freight forwarding agents to Nigerian customs officials.

[18] In September 2009, its Deepwater Horizon rig established a 35,050 ft (10,680 m) well, the deepest well in history – more than 5,000 feet deeper than its stated design specification.

However, since the company's 2007 merger with GlobalSantaFe, Transocean's reputation has suffered considerably, according to EnergyPoint Research, an independent oil service industry rating firm.

[28] On 2 March 2002, a Scottish man was killed in an accident aboard the Transocean Leader drilling rig operated for BP, located about 138 kilometers (86 miles) west of Shetland, Scotland.

[29] On 17 June 2003, one worker was killed, four others were hospitalised and 21 were evacuated after an explosion on a Transocean gas drilling rig in Galveston Bay, Texas.

[31] On 12 April 2007, the Bourbon Dolphin supply boat sank off the coast of Scotland while servicing the Transocean Rather drilling rig, killing eight people.

Louisiana Governor Bobby Jindal declared a state of emergency on 29 April, as the oil slick grew and headed toward the most important and most sensitive wetlands in North America, threatening to destroy wildlife and the livelihood of thousands of fishermen.

The head of BP Group told CNN's Brian Todd on 28 April that the accident could have been prevented and focused blame on Transocean, which owned and partly manned the rig.

It emerged that a "heated argument" broke out on the platform 11 hours before the accident, in which Transocean and BP personnel disagreed on an engineering decision related to the closing of the well.

[39] On 14 May 2010, US President Barack Obama commented, "I did not appreciate what I considered to be a ridiculous spectacle… executives of BP and Transocean and Halliburton [the firm responsible for cementing the well] falling over each other to point the finger of blame at somebody else.

[41][42] In response to broad criticism, including from Interior Secretary Ken Salazar, the company announced that its executives would donate the safety portion of the bonuses to a fund supporting the victims' families.

[43] The offshore drilling facility "Sedco 706", operated by Transocean under contract from Chevron, began to leak in November 2011 while working on the "Frade" oil field.

The Brazilian government sued Transocean and attempted to force the company to cease operations in Brazil, but a settlement was reached without a finding of fault or liability.

[45] In the early hours of Monday 8 August 2016, the semi-submersible drilling rig Transocean Winner ran aground near Dalmore in the Carloway district of the Isle of Lewis in the Outer Hebrides, Scotland.

Continuing poor weather meant that a damage inspection by salvors has been practically impossible, as personnel require to be airlifted on to the rig, in spite of it being close to the shore.

[48] Environmental monitoring of plant and animal life is on-going, particularly in view of the economically important fish farming operations in nearby Loch Ròg.