The GMC has set the mid-August deadline after only 58% of doctors let the regulator know whether they want a licence to practise.
Almost 86,000 doctors have failed to tell the GMC whether they want to work or not after November.
To practise in the UK after 16 November they need by law both a licence and a GMC registration, costing a total of £410 a year.
The great majority of doctors who have responded have told the GMC they do want the licence that will entitle them to practise medicine.
Just 3% of respondents have said they want to keep their GMC registration but not bother with a licence.
Doctors who fail to tell the GMC what they want will be automatically licensed.
Introducing licences marks the first formal step in the roll-out of revalidation.
- Is the GMC right to set a six-week deadline?
More news from 3 July