Oriel Môn is looking for new catering operators to run its cafe at Rhosmeirch, near Llangefni.
For the last four years, it has been leased out to Caffi Bach y Bocs - but the business, run by partners Ian Williams and Caron Ynyr, has decided not to bid for renewal.
The art gallery is now looking for an individual or company with "excellent catering experience" to take over from the current leaseholders after March 2027.
The owners of Caffi Bach y Bocs said they had decided to focus on other proejcts after nearly four "very happy years at Oriel Môn".
Ian and Caron added: "We're incredibly proud of what we've achieved at Caffi Bach Y Bocs and would like to thank Cyngor Sir Ynys Môn, our fantastic team and, most importantly, our wonderful customers - many of whom have become dear friends along the way."
"It's business as usual until 31st March, and we look forward to continuing to welcome you through our doors."
"Thank you for your support, kindness and friendship over the years. It's been a pleasure to be part of Oriel Môn, and we'll always look back on this chapter with great fondness."

The cafe at Oriel Môn, open every Tuesday to Sunday throughout the year, includes seating for over 50 people indoors and another 30 outdoors, weather permitting.
According to Anglesey Council, which runs the gallery, the lease provides an "exciting new business opportunity".
Kelly Parry, senior manager at Oriel Môn, said: "It has been a pleasure working with Ian and Caron for almost four years now. Their passion for quality and excellent customer service helped rejuvenate our café."
"Their staff and catering provision have been exceptional, and we'll be sad to see them go at the end of their agreement period. We'd like to wish Ian and Caron all the best for the future."
"This is an excellent opportunity to run a café situated in a museum and art gallery that attracts over 100,000 visitors a year."
"The special space that we have available, coupled with the high-quality foods and producers that are on offer locally, offers great potential. I look forward to seeing who will be creating a new menu for our visitors."
If you're interested in bidding for the lease, contact Kelly Parry at Oriel Môn on 01248 752 009 or e-mail orielynysmon@ynysmon.gov.uk


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