Internationally, it manages buses in several cities in Sweden, central and eastern regions of the Netherlands, and in the United States.

In 2014, Keolis won a 30-year public-private partnership contract to maintain and operate the Ion rapid transit in Waterloo, Ontario, Canada.

In the same year, Keolis won the operations and maintenance contract for Metrolink, the United Kingdom's largest tramway network, in Manchester,[1] and was also selected by Foothill Transit to operate and maintain the Municipal Transit Network for the Eastern San Gabriel Valley of Los Angeles County .

In October 2019, the Government of New South Wales announced that the bus operations of State Transit were to be contracted out to the private sector.

[16] Keolis Downer Northern Beaches (KDNB) commenced operating on 31 October 2021 with its contract to run for eight years.

In addition, under its own brand, Keolis provides shuttle bus services between Ottawa Train Station and Montreal Airport for Air France and KLM passengers.

Keolis is a partner in the GrandLinq consortium and operator of the Ion rapid transit system in Waterloo Region, Ontario.

In July 2024, Keolis announced that it is acquiring Pacific Western Transportation's Transit and Motorcoach operations.

[20] It would also be operating Shanghai Pudong International Airport's people mover system in 2019, which will link the proposed satellite concourse building with the existing Terminal 1 and Terminal 2, as well as the Songjiang Tram within the Songjiang Region, a suburb west of Shanghai downtown, in 2020.

During late 2014, the Danish authorities accepted the merger, permitting the two companies to merge as Keolis Danmark in the following year.

It provides transit services in many cities including Bordeaux, Dijon, Lille, Lyon, Orléans, and Rennes.

[27] Under the Eurobahn brand, Keolis operated multiple regional train services in the German state of North Rhine-Westphalia, Lower Saxony and in the Netherlands.

Eurobahn used Stadler Flirt electric multiple units and Bombardier Talent diesel cars to serve these lines.

[43] On 6 September 2022, DSD AS, the owner of Tide Buss announced they would buy out all shares in Keolis Norge and take over the running of all their contracts, leaving the company defunct.

[44] On 7 December 2017, Qatar Rail, the Qatari national public transport operator, awarded RKH Qitarat — the joint venture based on a consortium between RATP Dev and Keolis (49%) and the Qatari company Hamad Group (51%) — the operations and maintenance contract for the new automated metro of Doha, the capital of Qatar, and a light rail network in Lusail, the second largest city in Qatar, located 15 km from Doha’s city center.

[50][51] During 2012, Keolis lodged a joint bid with SNCF for the aborted InterCity West Coast franchise.

[62] On 31 May 2020, an Emergency Measures Agreement was approved to assist KeolisAmey Wales; it detailed that the Welsh Government will spend up to £65 million over the next six months to ensure trains continue to operate on the franchise.

[63] On 7 February 2021, the franchise was nationalised by the Welsh Government and transferred to a publicly owned operator of last resort, Transport for Wales Rail, with Amey retaining an involvement in delivering key infrastructure projects related to the Core Valley Lines.

In Nevada, Keolis operates bus services along the Las Vegas strip through a contract with the Regional Transportation Commission.

[65][66] However, during the bidding, a group of Holocaust survivors and Maryland politician Heather Mizeur called for investigations into SNCF's role in transportation of Nazi prisoners to concentration camps during the Second World War before the Keolis contracts could move forward.

Another group of Holocaust survivors, led by now-deceased Leo Bretholz also requested investigations of SNCF's involvement in the conflict.

[68] As a result, a law was passed to enforce this, leading to major criticism because SNCF had already documented their role in the deportation and had in fact released their archives for research and educational purposes in 1996.

The firm is expanding into new markets (through public calls for tenders in France and worldwide) and launching innovative initiatives in mobility.