According to newspapers De Tijd and L’Echo, the pair, which operate in Flanders and French-speaking Wallonia respectively, informed telecom regulator the IBPT at the end of May that they no longer intended to use the licence, for which they agreed to pay €71.5 million, with three-quarters of the investment coming from Telenet.
The pair acquired rights to use frequencies in the 2.1GHz range in 2011 that would have enabled them to offer 3G services.
Telenet and Voo justified their decision by saying that market conditions had changed and that the cost of infrastructure and the difficulty in obtaining permission to construct new antennas in urban areas made the plan unviable.
The pair had received a number of warnings over their failure to develop their own mobile network after being awarded the frequencies, which came with an obligation to provide coverage of 30% of the country.
Telenet separately operates an MVNO in partnership with mobile operators Mobistar.