Britain would have to keep free movement of people in order to stay in the single market, Plaid Cymru's Leanne Wood has said.
But she said there could be room for negotiation with Norway having restrictions on movement.
The party leader is to tell Plaid's conference that the UK should keep free trade with Europe so Wales' economy does not suffer after Brexit.
Leanne Wood will say 200,000 Welsh jobs depend on being in the single market.
She will also call for all four UK nations to be at the "top table" in negotiations on the terms of leaving the EU, and no loss of power for Wales.
Ms Wood will accuse the Labour Welsh Government of being "all over the place" in its response to Brexit.
Saturday, 22 October 2016
BBC News: UK must keep EU free movement, says Plaid's Leanne Wood