It is understood that at least 1,000 jobs are at risk at the chain as part of the restructuring plan.
The company said recent sales have dived by almost three-quarters – 74 per cent – compared with the same period last year.
Sales and footfall have been hit hard by a heavy reduction in the number of people travelling into city centres for office work, with more people working from home due to the pandemic.
Pret said it will also reduce the number of staff working across its remaining UK stores to reflect the slump in demand.
The Reading town centre branch in Broad Street will be among those to close.
The company said it has faced “significant operating losses” following the outbreak, despite having reopened over 300 of its sites.
Pret will soon start consultations with staff as it pushes forward with plans to shut these 30 sites in the second half of the year.
Its restructuring plan will see it launch a sale process for the lease of Pret’s main support office near London Victoria station.
Discussions are also ongoing with landlords across its estate to develop a more “sustainable” model, after external advisers were hired.
Chief executive Pano Christou said: “It’s a sad day for the whole Pret family, and I’m devastated that we will be losing so many employees.
“These decisions are not a reflection on anyone’s work or commitment, but we must make these changes to succeed in the new retail environment.
“Our goal now is to bring Pret to more people, through different channels and in new ways, so that we can continue to provide great jobs and opportunities to our remaining employees.”