It will move from Dolgellau to Tywyn on Wednesday, 16 December.
The aim of the centre is to ensure Meirionnydd residents have access to the Covid-19 testing as close as possible to their home.
The centre at Dolgellau’s Marian will be open until Tuesday, 15 December.
Gwynedd Council leader, Councillor Dyfrig Siencyn, said: “The arrangements of the mobile testing facility is working well and helps to ensure that the residents of Meirionnydd have access to a test as close as possible to home.
“As part of this aim, we are pleased to see that the mobile unit will be moving on to Tywyn, this has been achieved by working with a number of partners and we are grateful for their cooperation, especially Tywyn Town Council for helping to secure the site for the unit.
“It is a difficult time for anyone who has symptoms of the virus, and we hope that having a mobile unit located in the area is benefitting residents whilst we work to stop the spread of Covid-19 and protecting our health and care services.
“The unit offers tests for members of the public who have made an appointment, and we would remind residents that the facilities are only for those people who have symptoms.
“I would also remind residents to continue to follow the rules to keep the Covid-19 infection rate down - we can all play our part by social distancing, washing hands and wearing face coverings where required.”
The mobile unit is available for individuals who believe they have symptoms, and you should only attend if you have one or more of the following symptoms:
• a high temperature;
• a new, continuous cough;
• a loss or change to your sense of smell or taste.
The testing facility located at the Talyllyn Railway car-park on Cambrian Road in Tywyn will be in operation for the next two weeks, with plans to continue moving the mobile facility to other locations in the Meirionnydd area of the county to help ensure that access to testing is available as close to home as possible.
Teresa Owen, Betsi Cadwaladr University Health Board’s executive director of Public Health, added: “We are pleased to be working with Gwynedd Council to offer residents in the Meirionnydd area, who are experiencing symptoms of Covid-19, access to a test at our temporary Mobile Testing Unit in Dolgellau.
“This will ensure that residents in this area can access testing closer to where they live.
“Covid-19 is still circulating within our communities and it’s important that anyone who is experiencing symptoms of Covid-19 must self-isolate immediately and book a test.”
The testing facility will be open to people to use as a drive-in centre or to visit on-foot, but will only be open to those with an appointment. Signs will be in-place to direct the public to the facility.
Anyone attending the centre should wear a face covering.
Those visiting by car should keep their windows raised until asked to lower them – this will help to keep everyone safe.
The testing centre will be open 9.30am–3.30pm seven days a week.
Details about how to apply for a test can be found at https://gov.wales/apply-coronavirus-covid-19-test