Absent bosses could be restricting their company's ability to react to business opportunities and possible crises, according to research unveiled by T-Mobile.
The study found that the majority of small business decision-makers are out of the office for a minimum of two months a year, with 60% out for a minimum of five hours a week.
When taken on top of the average UK entitlement of 25 days' holiday, T-Mobile suggests company bosses are out of the office for the equivalent of 32.5 days a year.
With so much time on the road, many business owners now rely on mobile technology to stay in touch with developments back at the office.
"It's not until you actually add up all of the time spent out of the office that you realise it has the potential to put a real strain on business resources," said James Caan, chief executive of private equity firm Hamilton Bradshaw and Dragon for BBC Two's Dragons' Den.
"I literally couldn't run my businesses without mobile broadband and email. It's critical to my employees' ability to react quickly to opportunities and to ensure the right people can be reached at a moment's notice when important decisions need to be made."
But despite this reliance on mobile communications, the research also found that 42% of SME directors believe they pay too much for their package and 65% do not have the ability to control the cost of international calls from mobile phones.
"Small businesses are either paying too much or do not have policies in place to control the cost of mobile communications," said Oliver Chivers, head of business marketing at T-Mobile UK.
"This technology is there to support the business, not place a strain on the bottom-line. The survey uncovered that nearly a quarter of small businesses haven't reviewed their mobile comms plan in over a year, with 17 per cent completely unaware of when it was last checked.
"Mobile communications has moved on from bundles of minutes and texts; now it's about mobile internet, email and data sharing," he said. "Any business must ensure its mobile plans include quotas for voice, email, texts and international calls in order to support their employees' changing needs and to guard against unnecessary bill-shock."