The holiday home specialist said prospective owners should consider occupancy, taxation, running costs and potential regulatory changes when assessing whether a property represents a viable investment.
The comments come amid debate over Wales' 182 day occupancy threshold and the introduction of visitor levies in parts of the UK.
Laura Dubois of Together Travel said: "The biggest mistake a prospective holiday-let owner can make is looking at the headline nightly rate and assuming that tells you whether a property is a good investment.
"Holiday lets are seasonal businesses, and their profitability depends on much more than the price you can charge for a week in August.
"With the regulatory landscape changing, owners should be looking at the full picture, including occupancy, local demand, taxation, running costs and how future policy changes could affect the property."
Five things holiday let owners should check
1. Don't base calculations on peak season occupancy
Together Travel said owners should assess annual occupancy rather than relying on potential earnings during the busiest periods, particularly when considering properties in seasonal destinations.
Dubois said: "It is very easy to get excited about what a property can earn in July and August, but those figures can give a misleading impression of the annual return. Before buying, look at how demand changes throughout the year and whether there are genuine reasons people would visit outside of peak season."
In Wales, self catering properties generally need to be available to let for at least 252 days and actually let for at least 182 days in a 12 month period to qualify for non domestic rates rather than council tax.
A Senedd petition is calling for the 182 day threshold to be replaced with a 105 day requirement, while the Welsh Government has introduced greater flexibility around how the occupancy requirement can be met.
2. Check which tax rules apply
Prospective buyers should establish whether a property is likely to be subject to council tax or non domestic rates and factor this into their calculations alongside potential rental income and other costs.
Dubois said: "Tax should be part of the initial property research, not something you investigate after you've bought the property. If you're looking at a holiday let as a business, you need to understand what classification the property could fall under and what requirements you'll need to meet."
3. Check for existing or planned visitor levies
Owners and prospective buyers should also consider whether their chosen destination has introduced, or plans to introduce, a visitor levy.
Edinburgh introduced a 5% visitor levy on paid overnight accommodation for stays from 24 July 2026, while Cardiff is preparing to introduce a visitor levy from 1 April 2027. The Cardiff levy is set at £1.30 per person per night for most accommodation and 75p for campsites, pitches and shared accommodation.
Dubois said: "A visitor levy doesn't necessarily make a destination less attractive, but it is another cost and administrative consideration for operators. Anyone considering buying should understand whether a levy applies, when it is coming into effect and how it will be collected before building their financial projections around a property."
4. Assess demand outside peak season
Together Travel said investors should consider who is likely to use a property outside the summer months and whether its location and features could support demand throughout the year.
Features such as hot tubs, indoor entertainment spaces, pet friendly facilities and proximity to attractions or walking routes could potentially help generate bookings outside peak periods.
Dubois said: "A property's biggest asset might not be its ability to attract an expensive summer booking, it could be its ability to generate bookings in February, November or March.
"Owners should think about what makes their property relevant throughout the year and who their potential off-season customer is."
5. Allow for future regulatory changes
Prospective owners should also consider how changes to tax and regulation could affect the financial viability of an investment over the longer term, according to Together Travel.
Dubois said: "Nobody can predict exactly what the holiday-let landscape will look like in five or ten years, so I wouldn't recommend buying a property based on one very specific tax assumption.
"Build some flexibility into your calculations. If the property only works financially under the most optimistic occupancy figures and the most favourable tax treatment, that should be a warning sign.
"A strong holiday-let business should be able to stand up to some change."
Dubois added: "The conversation shouldn't simply be about whether holiday lets are being taxed more or whether there are more rules to follow. There is an opportunity here for the sector to become more professional and sustainable. Owners who understand their numbers, know their market and plan ahead are going to be in a much stronger position than those who rely on peak-season demand and hope the rules don't change.
"For prospective buyers in particular, the key message is to do your homework. The best holiday-let investment isn't necessarily the property with the highest possible weekly rate, it is the one with a sustainable business model behind it."
