A report published by Ofcom indicates only 38% of the country can get good 4G services from all operators - while 82% of England is covered.
The Scottish Government are aiming to deliver superfast broadband to every home and business by 2021.
The number of Scottish premises able to access a superfast connection has increased from 87% in 2017 to 92% this year.
The Federation of Small Businesses (FSB) has urged the UK Government and Ofcom to take stronger action to improve Scottish mobile coverage.
Andrew McRae, the FSB’s Scotland policy chair, said: “Consumers and businesses in Scotland are paying as much for their mobile phones as counterparts elsewhere in the UK for a service, which this report illustrates, is far worse.
“While it is good to see Ofcom note that this is unsatisfactory, we need to see action from them, the UK Government and mobile operators to address this long-standing problem.
“On the other hand, this publication also underlines that Scotland is making good progress on superfast broadband provision, though we still lag both England and Wales.
“We strongly support the Scottish Government’s ambition on this front, though we would underline that expectations amongst communities and firms are very high and they must deliver.”
Scottish Liberal Democrat Rural Economy and Connectivity Spokesman, Mike Rumbles, said: “You must keep your fingers crossed when driving home this Christmas that you aren’t caught in a 4G blackspot. As we rely increasingly on our mobiles, it is becoming a safety issue to have our rural countryside a 4G not-spot.
“The Scottish Government has made a lot of promises but has yet to deliver any meaningful change and it must speed up the glacial pace it has been taking to try to reach 100% superfast broadband coverage. It is our rural areas, which have been left to be provided for last.
“Reliable coverage of 4G and Superfast broadband is an investment into the future. The Scottish Government must get serious and provide rural areas with the coverage we all expect.”