When it comes to reserving hotel stays, Aesop and his fabled ants might have gotten it backwards — it can actually pay to wait till the last minute to book.

While conventional wisdom holds that travelers get better rates for accommodations, air and other vacation components by reserving early, research from NerdWallet found that 66% of the time they’d save more by waiting to book a hotel room until 15 days before arrival, compared to four months out.

The idea that booking early is better has actually always been more about choice, said Sally French, a travel expert at NerdWallet.

“It’s less about ‘buy earlier for better deals’ and more about the opportunity cost of not booking early — you could severely limit your options by waiting,” she said. “Booking in advance means you have more choice to book the hotel that’s truly in your budget.”

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NerdWallet studied more than 2,500 hotel room rates in 2019, 2020 and the first half of 2021 at hotels worldwide across price point and brand, comparing prices for nights 15 days and four months out.

From 2019 to 2021, the average room rate in North America booked 15 days out was $203, while that for a unit booked four months out was $233, NerdWallet found, a 12.7% difference. Internationally, the respective rates and difference were a similar $201 and $232, a 13.5% gap.

“International trends are mostly in line with domestic trends,” said French, adding it’s “comforting knowing you’re not missing out on even better international deals.”

The average rate at all high-end hotels, meanwhile, was $302 when booked 15 days before travel, compared to $386 four months ahead — a 21.6% difference. The difference is even greater — 50%, NerdWallet found — when comparing rates for 15 days ahead with 11 months before.

However, “cheaper” is a relative term, French noted. As an example, she pointed to pre-pandemic nightly rates at the JW Marriott Los Angeles L.A. LIVE, which were $1,110 when booked 11 months out and $450 just 15 days before.

“Still, $450 is more than most people are going to pay for one night at a hotel,” French said. “So while you might get a ‘better’ rate at that hotel, it’s often going to still be more expensive than a mid-range option.”

Savings at medium- and low-range hotels were more meager, at 9.4% and 5.5%, respectively. French said NerdWallet found that “budget friendly” hotels, such as the $100-a-night Best Western Market Center in Dallas — which never deviated from that rate in the course of the study — are less likely to vary in price even up to the last minute.

“But what happens if you think it’s OK to procrastinate, and then all the budget hotels get sold out because a huge festival or conference was in town?” French said. “You might have no choice but to book the Ritz-Carlton, which often goes for over $1,000.

“That’s a $900 mistake for waiting until the last minute,” she said.

Has the pandemic and ensuing downturn in travel helped keep rates down? French said prices fell about 33% year-over-year in 2020 but are now 30% cheaper than in 2019, meaning they’re on the rise.

“As more people get vaccinated and countries open up to tourists, I expect that trend to continue,” she noted. “If you feel comfortable traveling now, grab deals while you can because I don’t expect they’ll stick around.”

Travelers might want to consider booking direct with their hotel of choice, whether online or by phone. It’s less about price and more about flexibility, according to French. “Many hotels have super-generous cancellation policies these days, but it’s often only honored when the reservation was made with them,” she said. “It’s less of a guarantee that you’ll get a full refund when booked with a travel agent or a third-party site.”

In addition, most hotels will price-match cheaper rates for the same room and travel dates, according to French, or travelers with reservations at hotels with flexible cancellation policies can cancel more expensive reservations made earlier and rebook at cheaper rates. That said, booking at online sites is “certainly faster and more convenient,” she added.

Destinations with cheaper hotel rates include Bangkok and Tokyo abroad — where rates are still off 2019 prices by more than 50% — and, in the U.S., business centers like New York and Philadelphia, according to French.

Where to avoid?

“I’m seeing a lot of hotels — particularly in more remote, domestic destinations — that have actually gone up in price,” she said. “Two different luxury hotels in Scottsdale, Arizona, the Hyatt Regency Scottsdale Resort & Spa at Gainey Ranch and the Andaz Scottsdale Resort & Bungalows, both averaged about 80% more in 2021 versus their 2019 rates.”