The initial public offering (IPO) is expected to raise RO96.19m ($249.85m), after raising RO107.66m through a private placement earlier in the month.
Locals will be able to subscribe to the share offer, which is priced at RO1.35 per share, until 13 April.
The offering will bring the Omani governments stake down to 51 per cent. Bank Muscat is acting as financial adviser on the sale.
Omantels revenues grew 1 per cent to RO462.9m in 2013, while its profit increased 2.6 per cent to RO119m.
Challenges in its domestic market, where Omantel faces increasing competition from Nawras, a subsidiary of Qatar-based Ooredoo, prompted the operator to increase its capital expenditure in 2013 and 2014, to help fund infrastructure upgrades in Oman and its unit in Pakistan.