The surge in registrations comes after a one-month dip that saw the number of patients registered with the service fall by nearly 700.
In total, 26,515 patients were on the books at the Lillie Road Medical Centre in Fulham - where patients signing up for GP at Hand are registered - as of 1 May.
The latest sharp rise in registrations is likely to drive up pressure on the local health economy, after Hammersmith and Fulham CCG warned last month that it would need an £18m bailout from NHS England to cover the cost of thousands of young patients - mainly from outside the local area - joining the service.
The GP at Hand patient list grew by 2,518 in the month to 1 May - up more than 10% from the 23,997 total a month earlier.
Almost 1,100 patients aged 20-29 joined in the past month alone, and 50% of the total increase in patients registered at the practice since it opened the service to people across a broader swathe of London in November 2017 have been in this age group. A further 34% of new patients since November 2017 have been in the 30-39 age bracket.
The latest figures came as Londonwide LMCs chief executive Dr Michelle Drage warned that 'cherry picking' of young patients by GP at Hand was putting existing practices at risk.
GP at Hand and Babylon - the company whose technology the service relies on - have repeatedly said that 'patients and GPs are flocking to GP at Hand' because of its offer of 'high quality, digital-first 24/7 NHS GP services'.