Serial entrepreneur Sky Dayton, currently chief executive officer at Helio LLC, said he will step down from his position at the Santa Monica-based company, but will continue as chairman of Helio’s board.

Dayton has been at the helm of the upstart cellular phone maker for three years. His departure follows a pattern of his other companies; he made the same move at Internet service provider Earthlink Inc., after only two years into his role as chief executive.

Wonhee Sull, Helio’s former president and chief operating officer, is slated to take Dayton’s spot.

“Helio has reached a point in its development where I feel the timing is right for this change. … As we have for the past three years, the two of us will continue to define Helio’s direction and future,” Dayton said in a statement.

Helio provides cellular phone service by leasing access to Sprint Nextel Corp.’s high-speed network, making it a so-called “mobile virtual network operator,” or MVNO.

Several other startups have tried to use the MVNO business model, with companies such as Los Angeles-based Amp’d Mobile, Burbank-based Walt Disney Co.’s ESPN Mobile and Disney Mobile all closing in the past year and a half.