Mobilisation of 3D Seismic Programme

10 September 2026

Rift Helium plc

("Rift", "Rift Helium" or the "Company")

Rift Helium Mobilises 3D Seismic Programme

Rift Helium plc (AIM: RIFT), the primary helium exploration company focused on the Upepo Project in Tanzania's proven Rukwa Basin, is pleased to announce that mobilisation has commenced for its 3D seismic programme at the Company's flagship Upepo Project.

Highlights

·  Mobilisation of Rift's fully funded 3D seismic programme has commenced following receipt of the Environmental Impact Assessment ("EIA") certificate, with field acquisition planned to commence in Q4 2026.

·    The survey will create a detailed 3D picture of the subsurface structures at Upepo, helping Rift identify and rank the strongest targets and improve drilling decisions before capital is committed.

·    The resulting data will support an updated independent resource assessment targeted for Q1 2027 and finalise well locations ahead of the Company's two-well exploration programme planned for H1 2027.

·    Rift will use lightweight portable sensors and smaller field crews, which are designed to enable efficient data acquisition with little or no line clearing, reducing ground disturbance and health, safety and environmental exposure.

Charles FitzRoy, CEO of Rift Helium, commented:

"With the EIA now secured, we are moving directly into the next phase of field work. This is another clear step in delivering the programme we set out at IPO.

"Our approach is simple: use the best available data to improve drilling decisions before committing capital to exploration wells. The Rukwa Basin has already demonstrated a working helium system. Improved seismic data will allow us to better understand the underground structures at Upepo, identify those with the greatest potential to trap helium and focus our capital on the best targets.

"The seismic results will support our planned resource update and allow us to finalise the locations for our planned two-well exploration programme. We are progressing through a disciplined sequence - permit, map, rank and drill - with each step designed to reduce uncertainty before the next capital decision. We remain on track for the first exploration well in H1 2027."

The 3D seismic programme

Rift's strategy at Upepo is based on a simple principle: reduce uncertainty before drilling. The Company entered the Rukwa Basin after helium had already been demonstrated by other operators, allowing Rift to build on existing basin knowledge rather than explore a new helium province from first principles. This "third-mover" approach is central to Rift's strategy.

Existing geological information and 2D seismic data have identified five exploration leads across the Upepo Project, primarily on the eastern licence, PL12093/2022. While 2D seismic provides individual cross-sections through the ground, the planned 3D survey will create a more complete picture of the structures beneath Upepo. This will allow Rift to better define their size, shape and boundaries and identify faults or breaks that may affect whether helium can be contained.

3D seismic does not directly confirm the presence of helium; its role is to map the underground structures in which helium may accumulate. By combining the new 3D data with Rift's existing geological information, the Company expects to rank the strongest targets, improve confidence in their estimated size and select the most appropriate locations for drilling. This is designed to improve the quality of Rift's drilling decisions and focus capital on the highest-priority targets.

The resulting dataset is expected to support an updated independent resource assessment targeted for Q1 2027. Rift's current independent prospective resource estimate includes a mid-case (P50) estimate of approximately 19 billion cubic feet (Bcf) of helium and a mean estimate of approximately 41 Bcf. The updated interpretation will inform final locations for the two-well exploration campaign, with the first exploration well planned for H1 2027.

For further information, please visit www.rifthelium.com or contact:

About Rift Helium:

Rift Helium is building a new source of primary helium for the industries that depend on it. Helium is essential to high-value applications including semiconductor manufacturing, MRI, aerospace and emerging quantum technologies, yet much of global supply is produced as a by-product of hydrocarbons and is concentrated among a relatively small number of sources.

Rift is focused on dedicated primary helium - helium developed independently of hydrocarbon production. The Company's 283 km² Upepo Project is located in Tanzania's Rukwa Basin, adjacent to confirmed helium discoveries. Rather than exploring a new basin from scratch, Rift is applying a disciplined third-mover strategy: build on a proven helium system, use modern 3D seismic to identify and rank the strongest structures, and then focus drilling capital on the highest-priority targets.

Rift's pathway is clear: 3D seismic in 2026, an updated resource assessment and final drill-location selection in Q1 2027, followed by a fully funded two-well exploration programme in H1 2027. The EIA Certificate covers drilling of up to three exploration wells. In the event of exploration success, Rift's objective is to progress Upepo toward commercial production and establish a new source of primary helium from Tanzania, strategically positioned to serve high-value international markets including Asia.