First Minister Carwyn Jones has warned a no-deal Brexit could be "hugely expensive" for Wales because of potential disruption to sea links.
The First Minister was speaking at the British-Irish summit when he said leaving the EU with no-deal could disrupt sea links with Ireland - a warning he's made in the past.
Mr Jones said that 70% of trade between Great Britain and Ireland passed through Welsh ports like Holyhead.
Mr Jones made the comments at the British-Irish Council summit on the Isle of Man. Leaders from Ireland, Scotland, Northern Ireland, and the crown dependencies discussed a number of issues, but the impact of Brexit on trade was high on the agenda.
The outgoing First Minister made reference to the car business Schaeffler, saying it was an example of how uncertainty due to Brexit may impact business. Mr Jones said Brexit uncertainty was a key factor in the firms decision to close a plant in Llanelliwith the loss of 220 jobs.
The UK's de facto deputy prime minister David Lidington said that East-West commerce across the Irish Sea was economically far more important than the more high-profile North-South movements between Northern Ireland and the Republic.
The Irish Taoiseach, Leo Varadkar, warned Irish freight heading for the continent may be forced to switch to sea routes to French, Dutch and Belgian ports rather than taking the quicker "land-bridge" via Britain to Calais.