A large proportion of its design is based on the Electrostar, adding new technologies and achieving compliance with more stringent requirements and operator demands.

Bombardier began developing the Aventra in 2009 based on feedback from train operating companies (TOCs) and upcoming regulation changes.

Numerous other operators have since ordered the type, including London Overground, Greater Anglia, South Western Railway, c2c and West Midlands Trains.

The Aventra was developed by Bombardier Transportation principally as a successor to their prolific Electrostar electric multiple unit (EMU) family, the final example of which was delivered during 2018 after nearly twenty years of continuous production.

[5] According to Niall Simmons, Bombardier's Head of Bids Engineering, development work on what would become the Aventra had begun as early as 2009, although its design had significantly evolved during this time[5] in response to the feedback gathered from various train operating companies.

The platform was to be made adaptable to serve various subsections of the passenger rail market, including inter-regional, commuter, metro, and high-speed services.

[9] While the older Electrostar family are not compliant with the Technical Standards of Interoperability (TSI) introduced in 2017, the Aventra was specifically designed for compliance with the more rigorous regulatory requirements.

This bi-mode trainset, which would have incorporate batteries, positioned itself as a potential successor to several older diesel multiple-units, such as the Bombardier Turbostar and Voyager platforms.

[5] Each operator can choose to customise the design of its Aventra fleet; common variations have included different vehicle lengths, modified propulsion systems, and interior changes.

Some customers, such as the London Overground, have intentionally stylised their Aventra's interiors to maintain a high degree of commonality with their existing Electrostar fleets.

[15] In April 2024, with the future viability of the Derby Litchurch Lane manufacturing plant in serious doubt due to a lack of orders, a further follow-on order for 10 additional trains was indicated (5 previously agreed plus a further 5 trainsets making a total of 10 trains) in response to strong growth of passenger numbers on the Elizabeth Line and future expected service increases to cope with the interchange with High Speed 2 services at Old Oak Common Interchange.