Only a handful of museums and galleries are expected to reopen as coronavirus restrictions are lifted.
Some of Wales' most popular cultural sites are allowed to welcome visitors again from Monday.
But National Museum Wales' attractions will return from 4 August, while some smaller museums are staying closed until 2021.
The Federation of Museums and Art Galleries of Wales said reopening was a "complex and costly business".
Visitors attending museums and galleries will have to respect social distancing measures, while ticketing systems are being introduced at some sites to control numbers.
The visitor experience is also being adapted, with some areas likely to be closed off where a safe distance cannot be maintained.
The galleries at Oriel Plas Glyn-y-Weddw in Llanbedrog, Gwynedd, will reopen on Monday, one of the few sites to do so on the day restrictions are lifted.
Director Gwyn Jones said lockdown has had a "huge impact" on business.
"Because we are largely self-financing, we rely heavily on the trade we can generate between Easter and October," he said.
"That's when we make a profit, and naturally we make a loss over the winter. So it has had a huge impact on the centre itself."
In recent weeks the gallery has been able to open its café with a takeaway menu, but it needs visitors to return in order to increase its income.
Mr Jones added: "We have had help from the Welsh Federation of Museums and the Welsh Government to make sure we have the signage in place, the PPE (personal protective equipment) in place - we have spent over £1,000 on PPE which is a considerable amount for us, but we had to do it.
"We will have a steward welcoming people on the door, taking track and trace information, and we will allow 20 people at a time into the gallery."
'We've missed it so much'
National Museum Wales has already announced the staggered reopening of its seven sites around Wales, beginning on 4 August with St Fagans National Museum of History in Cardiff.
The director general, David Anderson, said he was "really proud" to be able to reopen the doors.
"For those of us who work in the museum, we have missed it so much. We know a lot of people have really missed it too," he said.
"We have been open online and we have been providing services by all sorts of other means. But there is nothing like being in St Fagans, with the buildings around us and being able to walk around in this incredible, iconic space."
Visitors will need to pre-book a free ticket in advance and will have to respect a one-way system around the St Fagans site.
Only its outdoor areas will be open and visitors will not be allowed to enter the historical buildings dotted around the museum grounds.
Mr Anderson added: "We are really mindful of our responsibility, as a public museum, for the health and safety of our visitors and staff.
"We have done everything that we can to design the experience in a way that will keep people safe and I hope that people will feel confident when they come to us that they will see that we have done that as well.
"It does mean the experience is different. But I think we would say that it is far, far better to open part of St Fagans than to keep it closed."
How will smaller venues cope?
Others have yet to set a date to open their doors. Many have relied on funding from the Welsh and UK governments to keep afloat since March.
Information has been shared among them by the Federation of Museums and Art Galleries of Wales, an umbrella body which has kept members informed of the support that is available and the restrictions on their activities.
Victoria Rogers, president of the Federation of Museums and Art Galleries of Wales, said: "Reopening is actually a complex and costly business.
"The Welsh museums sector is a vibrant mix of all types of museums and all sorts of shapes and sizes and that is going to have a real impact on how many will be able to reopen quickly.
"We know from our members that some are taking a bit more time to think about how they reopen safely for their staff, their visitors and their volunteers.
"There will be other museums that are really having to balance that need for income generation versus the costs of reopening, with the enhanced cleaning, additional staffing and the PPE that is required. So some museums will struggle with those costs."
Ms Rogers warned that some museums, particularly smaller attractions, would not reopen until the 2021 season.
Among the museums waiting until next year is Tenby Museum.
The chair of trustees, Councillor Michael Williams, said the museum had examined various options for reopening "but none of them offer a viable and essentially safe environment on which we could do so".