British Prime Minister Keir Starmer said the virtual meeting chaired by Foreign Secretary Yvette Cooper "will assess all viable diplomatic and political measures we can take to restore freedom of navigation, guarantee the safety of trapped ships and seafarers and to resume the movement of vital commodities".
Iranian attacks on commercial ships, and the threat of more, have halted nearly all traffic in the waterway that connects the Persian Gulf to the rest of the globe's oceans, shutting a critical path for the world's flow of oil and sending petroleum prices soaring.
The US is not among the countries attending Thursday's meeting.
Trump has said securing the waterway is not America's job, and told US allies to "go get your own oil".
No country appears willing to try and open the strait by force while fighting rages and Iran can target vessels with anti-ship missiles, drones, attack craft and mines.
But Starmer said on Wednesday that military planners from an unspecified number of countries would meet soon to work on how to ensure security for shipping "after the fighting has stopped".
In the meantime, 35 countries including the UK, France, Germany, Italy, Canada, Japan and the United Arab Emirates have signed a statement demanding Iran stop its attempts to block the strait and pledging to "contribute to appropriate efforts to ensure safe passage" through the waterway.
Thursday's meeting is considered a first step, to be followed by "working-level meetings" of officials to hammer out details.
Starmer said resuming shipping "will not be easy", and would require "a united front of military strength and diplomatic activity" alongside partnership with the maritime industry.
The international effort idea has echoes of the international "coalition of the willing" that has been assembled, led by the UK and France, to underpin Ukraine's security after a future ceasefire in that war.
The coalition is, in part, an attempt to demonstrate to the Trump administration that Europe is stepping up to do more for its own security.
The urgency of stronger continental defences has been reinforced by Trump's renewed suggestion that the US could pull out of NATO.
