The government said it will deport migrants to Rwanda in two weeks on 14 June.
The Home Office said it had begun issuing formal removal notices to migrants as the “final administrative step” in its partnership with the east African nation.
The home secretary said that there would still be attempts to delay the process.
Priti Patel said: “Our world-leading partnership with Rwanda is a key part of our strategy to overhaul the broken asylum system and break the evil people-smugglers’ business model.
“Today’s announcement is another critical step towards delivering that partnership and, while we know attempts will now be made to frustrate the process and delay removals, I will not be deterred and remain fully committed to delivering what the British public expect.”