UK Customs Declaration Service: 2025–2026 Outage Calendar and Impact on Declarants

What You Need to Know

The industry has seen a series of maintenances and technical incidents affecting the UK Customs Declaration Service (CDS) since 2023. A planned outage will take place from March 28, 2026, 8:00 p.m. to March 29, 5:45 a.m. Primary source: HMRC, updated April 13, 2026 (HMRC, Customs Declaration Service: service availability and issues).

Key Points

• 11 scheduled maintenance periods and 14 unplanned incidents recorded between January 2023 and April 2026 (source: HMRC)
• From March 28, 2026, any pre-lodged customs declaration not updated prior to arrival will be rejected and may delay release of goods (source: HMRC)
• The profession faces delays during maintenance windows: messages and requests are queued and processed later. Movements requiring Defra approval experience specific delays (HMRC, February 12 and February 18, 2026)

Background and Challenges

The CDS is the central platform for declaring import and export movements in the UK. Since the UK’s exit from the EU, any error or service disruption impacts customs flow, especially for declarants handling high volumes and operators using the Goods Vehicle Movement Service (GVMS). HMRC requires pre-lodged declarations to be kept up to date: those not updated before arrival are rejected (update of March 28, 2026, HMRC). At the same time, similar delays are observed on other customs systems in Europe, notably the EU Entry-Exit System, which has caused queues over three hours at several airports since its go-live on April 10, 2026 [Hotel News Resource, 13/04/2026].

Impact on the Profession

The profession must anticipate outages in advance, stagger declaration lodgement timings, and inform clients about the risk of rejection for non-updated files. Declarants must ensure compliance of all files, especially prior to arrival, to avoid automatic rejection and delays in goods release. Freight forwarders operating at GVMS locations can only finalize movements with a validated Goods Movement Reference during outages (HMRC).

Next Steps

• Scheduled maintenance from March 28, 2026, 8:00 p.m. to March 29, 2026, 5:45 a.m. Declarants should avoid lodging documents during this window
• Declarants must systematically check that pre-lodged declarations are updated before arrival from March 28, 2026
• In the event of a CDS incident, follow HMRC contingency procedures and report operational issues within required timeframes

Depuis le 28 mars 2026, tout dossier pré-lodgé non actualisé avant arrivée est rejeté – impact pour la fluidité douanière. (Since March 28, 2026, any pre-lodged file not updated before arrival is rejected – impact on customs flow.)

Source: HMRC, Customs Declaration Service: service availability and issues, consulted 13/04/2026. Supplemented by Hotel News Resource, 13/04/2026, on EU impacts.