The principal differences of the EC225 from the preceding AS332 are the adoption of Spheriflex rotor technology and new Turbomeca Makila 2A turboshaft engines, along with a redesigned main gearbox to accommodate the rotor and engine changes, and the addition of an integrated flight display system; these changes resulted in higher speeds and passenger comfort, as well as greater flight safety and reduced operating costs.

[5] In December 2015, the H225, a new designation used for the EC225, received certification from the Interstate Aviation Committee of the Commonwealth of Independent States; this made the H225 the first foreign heavy-lift helicopter to become certified in Russia.

[12] The EC225 is based on the Eurocopter AS332L2 Super Puma, improving upon the design with a five-blade main rotor incorporating a new airfoil shape to reduce vibration and noise levels.

[5] Energy absorbent self-sealing fuel tanks are contained in the aircraft's sponsons, along with other equipment such as downward-facing illumination and navigation lighting fixtures.

[13] The transmission can accommodate more power than the maximum output of the engines;[13] however two aircraft were lost in 2012 due to the cracking of the bevel gear shaft, a gearbox component.

[13] The advanced helicopter cockpit and avionics system is described as serving to reduce pilot and crew workload, being used to display flight management and sub-systems information and is complete with a four-axis digital autopilot.

[13] In January 2005, Algeria became the first country to use the EC225 when the Algerian Ministerial Air Liaisons Group (GLAM) took delivery of a single helicopter for VIP transport duties.

In this role, aircraft are typically equipped with a Dual Rescue Hoist, FLIR camera, high-powered searchlights and an advanced autopilot with autohover capability.

[25] The EC225 has also been used as an aerial firefighting platform, it can be equipped with a Simplex Aerospace-developed water cannon for dealing with fires in built-up urban areas, both Japan and South Korea operate several aircraft adapted in this manner.

On 25 October 2012 it was announced that the problem was suspected to relate to the main gearbox vertical shaft; the AS 332 L1 and L2 versions of the Super Puma could be refitted with an older design, allowing them to resume flying.

[31][32] By mid-2015, all 49 EC225s operating in the North Sea fleets in the UK had been retrofitted with a redesigned bevel wheel vertical shaft to avoid any recurrence.

[33] In March 2015, the Japan Coast Guard accepted delivery of its fifth and final EC225; outfitted for performing search and rescue missions, they shall also be used for security enforcement, territorial sea enforcement/monitoring and disaster relief operations.

[40] In October 2016, the grounding order by the EASA was lifted; some countries, including the United Kingdom and Norway, chose to maintain operational restrictions for the type.