Herne XLAUV

The Herne XLAUV (extra-large autonomous underwater vehicle) is a large-displacement autonomous submarine-shaped robot developed by BAE Systems in the United Kingdom. Extra-large autonomous underwater vehicles occupy a distinct class between conventional torpedo-sized AUVs and full-sized submarines; their size allows them to carry substantial payloads, operate for extended durations, and deploy sub-systems without surface support. The Herne programme has been developed for the Royal Navy under the XLUUV (extra-large unmanned underwater vehicle) category.

As of April 2026, BAE Systems described the Herne XLAUV as on track for Lloyd's Register certification and 2026 delivery at the Undersea Defence Technology (UDT) conference. Lloyd's Register certification is a third-party assurance that the system meets international safety and engineering standards, a prerequisite for operational Royal Navy deployment.

Herne's absence from the AUKUS Pillar II Signature Project fact sheet of 30 May 2026 was notable: the programme named two US-built platforms (Mission Specialist Defender Mk IV ROV and L3Harris Iver4 900 AUV) with no UK system listed, despite Herne's expected delivery in the same year. The omission raises questions about whether BAE Systems' XLAUV will secure trilateral programme status or remain a purely bilateral UK-Royal Navy capability. No official explanation was offered in the fact sheet.