Founded in January 1984, Garstang in 2016 became the first TTG Top 50 UK & Ireland's No.1 Travel Agency.
The agency will continue to operate and trade under its existing name and branding as part of Althams Travel Group.
It will also remain in its existing premises, with all nine members of the team retaining their roles.
"After 42 incredible years, it’s the right time to sell," said Eaves. "I leave knowing the business is in great hands.
"I’m excited we’re now part the Althams family, headed up by Sandra McAllister. Their focus on people and passion for travel means my great team and our wonderful clients will be in the very best hands."
Eaves will stay on with Garstang to oversee a smooth handover before "stepping into retirement".
Althams managing director McAllister added: "We are thrilled to welcome Garstang Travel and Nicole’s fantastic team into the Althams Family.
"Their outstanding reputation for customer care, personal service and community spirit, aligns perfectly with our own values. Nicole has built something truly special over the past 42 years, and we are honoured to continue her legacy."
