The four-star Kingsley by Thistle - formerly Thistle Bloomsbury - is located in London near Covent Garden, The British Museum and Oxford Street.
It has 129 bedrooms and six meeting rooms – the largest holding up to 100 delegates.
The guide price is £42m for the recently refurbished hotel.
Meanwhile, the four-star Thistle Brighton has 210 rooms, nine meeting rooms and a health and leisure club with pool.
Its guide price is £30m and both hotels are being offered for sale with a Guoman management contract in place.
CBRE Hotels marketing consultant Emily Newman said the sales are expected to be completed "before the summer break".