Do goods from Ireland to Poland need import clearance?

No. Ireland and Poland are both in the EU customs union, so the movement is intra-EU: no duty and no import declaration. A document is needed only when the truck travels overland through Great Britain (T2 transit) or when the customs authority at the EU port of entry requires a T2L proof of Union status on a direct sailing.

What is the difference between a T2 and a T2L?

A T2 is a transit procedure: Union goods cross a third country under customs supervision, with a guarantee, an MRN and closure at the office of destination. A T2L is a document confirming the Union status of goods, used when the goods enter no third country but customs wants confirmation of status, for example after a voyage through third-country waters. A T2LF covers territories with a separate fiscal status.

What happens if a truck from Dublin enters France without a transit?

The customs authority at the port of entry may treat the goods as non-Union goods, because they arrived on a ferry from Great Britain. The trailer is held until the status is clarified, which means waiting time and cost, and at worst a demand for charges as on non-Union goods. That is why we open the transit while still in Ireland, before boarding for Holyhead.

Ireland to Poland via GB: T2 and T2L

Goods from Ireland to Poland are an intra-EU movement: no duty and no import clearance. Formalities arise only when the truck travels overland through Great Britain. Union goods then cross GB under a T2 transit, opened in Ireland and closed in the EU, and a GMR in GVMS is needed to enter GB. On a direct ferry through third-country waters the customs authority may require a T2L proof of Union status. Without a document, goods entering the EU from GB may be treated as non-Union goods and held until their status is clarified.

Why can a truck from Dublin be taken for a truck "from the UK"?

For the customs authority at Dunkirk or Calais, a trailer rolling off the ferry from Dover is a trailer from Great Britain, that is from a third country. Nothing about it shows that the load was put on in Dublin and was never in British circulation. By default, goods entering the EU from a third country are non-Union goods and subject to an import declaration with duty and VAT. Only a transit document or a proof of status reverses that assumption and shows that the goods are Union goods that merely crossed GB.

That is why the Ireland to UK to Poland route needs more attention than the same route in the other direction. Leaving Poland, everybody remembers the transit, because without a GMR the driver does not board the ferry. Coming back from Ireland the temptation is greater: loaded in the EU, unloaded in the EU, why bother with documents? The answer is: because there is a third country in between.

When is it a T2 transit, and when a T2L proof of status?

A T2 transit is used when Union goods physically cross the territory of a third country, that is on the landbridge from Dublin via Holyhead and Dover. The declaration is opened in Ireland, the customs agency provides the guarantee, an MRN is issued, and the procedure is closed at the office of destination in the EU, usually already in Poland. The United Kingdom is a member of the common transit procedure, so one declaration covers the whole route.

A T2L proof of Union status covers a different situation: the goods do not enter a third country, but their route runs through third-country waters, or the customs authority at the EU port of entry requires confirmation of status. A T2L (and a T2LF for territories with a separate fiscal status) confirms that the goods are Union goods and are not liable to charges on their return to the EU customs territory. Whether such proof is needed on a specific direct sailing depends on the requirements of the customs authority at the port of arrival and must be checked before departure, not at the ramp.

The Ireland to UK to Poland route step by step

Confirm the status of the goods in Ireland. Goods produced in the EU or released for free circulation in the EU have Union status and travel on a T2; non-Union goods, for example imported into Ireland without release, travel on a T1.
Open the T2 transit before the ferry from Ireland. The OTSL customs agency lodges the declaration with a guarantee at the office of departure in Ireland; an MRN is issued and the driver receives the accompanying document.
Prepare the GMR to enter GB. OTSL creates the GMR in GVMS with the MRN and the vehicle registration; without it the truck does not board for Holyhead. The scope of the PBN for the Ireland to GB direction is checked against Revenue's current guidance.
Cross GB without unloading. Goods under transit may not be unloaded or transferred without customs consent; seals and document stay intact until the office of destination.
Notify entry into the EU. Before the ferry from Dover the carrier meets the requirements of the EU port of entry (France or Belgium) for a vehicle under transit, and the MRN identifies the goods as Union goods under procedure.
Close the transit in Poland. The goods are presented at the office of destination or to an authorised consignee; OTSL follows up the closure confirmation and the release of the guarantee.

Definitions

Union status: the attribute of goods produced in the EU or released for free circulation in the EU; when crossing a third country it must be proven by a document.
T2: transit of Union goods through a third country under the common transit procedure; T1 applies to non-Union goods.
T2L and T2LF: proofs of the Union status of goods; T2LF for territories that belong to the customs union but have a separate fiscal status.
MRN (Movement Reference Number): the number of the transit declaration, entered in the GMR and presented at the ports.
GMR (Goods Movement Reference): the reference in the British GVMS (Goods Vehicle Movement Service) required for a laden vehicle to enter GB, also from Ireland.
PBN (Pre-Boarding Notification): the notification in the Irish Revenue service for ferry traffic between Ireland and Great Britain; its scope for the IE to GB direction follows Revenue's current guidance.
Office of destination: the customs office (or authorised consignee) where the goods are presented and the transit closed.

Checklist before loading in Ireland

Status of the goods confirmed by documents: Union (T2) or non-Union (T1).
Route settled: landbridge through GB (T2 transit) or direct ferry (T2L if the port of entry requires it).
Holder of the procedure with an EORI (Economic Operators Registration and Identification) and a guarantee named; MRN available before boarding.
GMR with the MRN and vehicle registration created before the Irish port; PBN per Revenue guidance.
CMR (the Convention on the contract for international carriage of goods by road), invoice and packing list consistent with the transit on package count and weight.
Office of destination or authorised consignee in Poland agreed, and the person confirming closure.

Is a transit document needed on every route from Ireland?

No. A T2 transit does not apply to a direct ferry from Ireland to France if the goods enter no third country; they then travel like any Union goods, unless the customs authority at the port of entry requires a T2L proof of status because of a voyage through third-country waters. Transit is, however, required on every overland route through Great Britain, whether the crossing takes a few hours or a few days. The choice between T2 and T2L therefore depends on the route and the requirements of the EU port of entry, and the consequence of omitting the document is the same in both cases: a hold while status is clarified and the risk of charges as on non-Union goods.

The OTSL role

OTSL runs the Ireland to UK to Poland routes in both directions. The OTSL customs agency opens the T2 transit in Ireland, issues the proof of status where required, creates the GMR and follows up closure of the procedure in Poland as part of its customs clearance service. The difference between T1 and T2 is explained in T1 or T2 transit, and the proof of status itself in T2L and the customs status of Union goods. What a real import from Great Britain looks like, that is British goods going to Poland, is described in import from the UK to Poland. The lane overview is on the transport to Ireland page.