Z-Nummer, B-Nummer, S-Nummer — Hamburg Export Numbers Explained

If you export through the Port of Hamburg, you will encounter three distinct registration numbers: Z-Nummer, B-Nummer, and S-Nummer. These numbers are specific to Hamburg's port community system and play a critical role in the automatic MRN closure process. Understanding what each number represents and how they interact can help you avoid delays in obtaining your CC599C/IE599 proof of export.

Hamburg's Unique Registration System

Hamburg's port community system (historically known as ZAPP, now transitioning to EMP) uses a three-layer registration structure to track exports. Each layer represents a different participant in the export chain, and all three must align for the system to automatically close an MRN.

This system differs from other European ports. Rotterdam uses a single MED registration, Antwerp uses APCS with its own structure, and Bremerhaven uses BHT. Hamburg's three-number system is more granular, which offers finer control but also creates more potential points of failure.

Z-Nummer — Customs Export Registration

The Z-Nummer (“Zoll-Nummer” — customs number) is the customs export registration in the Hamburg port system. It is the digital link between the EU export declaration (MRN) and the Hamburg port system. Think of it as the port system's acknowledgment that an export declaration exists for a specific container.

Key characteristics:

• Created by: the customs agent or freight forwarder with port system access.
• Contains: MRN, container number, exporter details, goods description, customs office of export.
• Purpose: registers the export in the port system so the system knows to look for this container on the vessel manifest.
• Without Z-Nummer: the port system has no knowledge of the export declaration, and automatic matching cannot begin — the MRN will remain open indefinitely.

The Z-Nummer is the most critical of the three numbers from an MRN closure perspective. Missing Z-Nummer registration is the single most common reason for unclosed MRNs in Hamburg. For more, see our Z-Nummer knowledge base article.

B-Nummer — Booking Registration

The B-Nummer (“Buchungs-Nummer” — booking number) represents the carrier's booking in the port system. It links the physical container to a specific booking with the shipping line, including the vessel name, voyage number, and expected departure date.

Key characteristics:

• Created by: the freight forwarder or carrier's agent.
• Contains: booking reference, container number, vessel name, voyage number, terminal.
• Purpose: tells the port system which vessel the container is booked on, enabling the system to look for the container on that vessel's manifest.
• Without B-Nummer: the port system cannot link the Z-Nummer (customs registration) to a specific vessel, and automatic matching fails.

S-Nummer — Vessel Reference

The S-Nummer is a vessel reference number in the Hamburg port system. It represents the carrier's declaration of which containers are loaded on a specific vessel — essentially the vessel manifest as registered in the EMP/ZAPP system.

Key characteristics:

• Created by: the carrier (shipping line) or their port agent.
• Contains: vessel identification, voyage number, list of all containers loaded, departure date and time.
• Purpose: confirms which containers actually sailed on which vessel, providing the final piece of data needed for automatic MRN closure.
• Without S-Nummer: the port system cannot confirm that the container actually departed, and the export procedure remains open.

How the Three Numbers Connect for MRN Closure

Automatic MRN closure in Hamburg requires all three registrations to align:

1. The Z-Nummer tells the system: “There is an export declaration (MRN) for container ABCD1234567.”
2. The B-Nummer tells the system: “Container ABCD1234567 is booked on Vessel X, Voyage Y.”
3. The S-Nummer tells the system: “Vessel X, Voyage Y has departed with container ABCD1234567 on board.”

When the port system can match all three — Z-Nummer to B-Nummer to S-Nummer via the common container number and vessel — it confirms the export automatically. Hamburg Customs then sends the IE518/CC518C message to the customs office of export, triggering the generation of CC599C/IE599.

If any of the three numbers is missing, contains errors, or cannot be matched to the others, the automatic process fails and the MRN remains open.

Comparison Table

Common Problems with Hamburg Export Numbers

1. Missing Z-Nummer — the most frequent issue. The customs agent filed the export declaration but the freight forwarder did not register the Z-Nummer in the port system. Solution: have the forwarder create the Z-Nummer registration.
2. Container number mismatch between Z and B — a transposed digit or incorrect check digit means the Z-Nummer and B-Nummer reference different containers. The system cannot match them.
3. Vessel change not updated in B-Nummer — the carrier moved the container to a different vessel, but the B-Nummer still references the original vessel. The S-Nummer from the actual vessel cannot be matched.
4. Late S-Nummer from carrier — smaller carriers may not transmit the vessel manifest promptly, delaying the S-Nummer creation and, consequently, MRN closure.
5. Multiple Z-Nummern for one container — in rare cases, duplicate registrations create confusion in the matching process. This typically requires manual resolution by a port system specialist.

FAQ — Hamburg Export Numbers

Information about Hamburg port registration numbers based on publicly available documentation and operational experience. The ZAPP/EMP system is administered by Dakosy AG on behalf of the Port of Hamburg. Legal basis for export procedures: Art. 269-274 of Regulation (EU) No 952/2013 (UCC); Art. 329-334 of Commission Implementing Regulation (EU) 2015/2447. Updated: March 2026.