A hidden United benefit will extend your trip for next to nothing

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The Excursionist Perk is a United Airlines benefit that lets you stretch your miles further to get an extra flight.

• United's Excursionist Perk lets you add an extra flight in your destination region for no extra miles.
• It doesn't require any extra steps to use, only that you book with miles and create a multi-city itinerary.
• If you have miles from the United Explorer Card or another source, like points transferred over from the Chase Sapphire Preferred Card, this is a great way to stretch their value.

If you have the United Explorer Card like I do, the Excursionist Perk is a great way to get more from your miles. The Excursionist Perk adds an extra flight to a multi-city itinerary for no extra miles.

For me, this helped to extend a recent trip to Greece to see Italy as well for just 60,000 miles and under $150 in taxes.

The best part is that it's so simple to use. There's no need to enter any promotional codes - all it requires is booking with miles through United's site in order for the Excursionist Perk fare to take effect automatically.

Here's how it works.

First, pick two destinations to visit within the same region

You'll need to choose a place within the same region as your destination. United breaks the world into 17 regions. When you travel within your destination region, that flight (or one of them, if you're choosing more than three stops) will cost no extra miles thanks to the Excursionist Perk.

In my case, I chose another destination within the Europe region. But, it works anywhere when you travel within the same region. For example, you could fly from San Francisco to Hong Kong, then use the Excursionist Perk on a zero-mile flight to Singapore, before heading back to North America. Both Hong Kong and Singapore are in United's "South Asia" region, so the perk will apply.

The perk is pretty open-ended on time frame, and the only real stipulation is that your zero-mile Excursionist Perk flight is within the same region as your destination. You can't use it to stop over in another city in the region your flight is originating from. For example, the Excursionist Perk won't allow you to fly from San Francisco to Asia and then use the perk to make a stop in Los Angeles before heading back to San Francisco, as Los Angeles is in the same region as your origin.

Once you've got your stopover in your destination region picked out, you're ready to start planning.

Then, make a multi-city itinerary

At least three destination segments need to be included for the Excursionist Perk to kick in.

Here's the process I used to book my flight for my multi-city trip, where I traveled from Seattle to Athens, then on to Rome for zero miles, and then back home to Seattle.

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The Excursionist Perk only works when you book with miles, so make sure that that option is selected. And if you need more miles, remember that you can transfer points over from Chase Ultimate Rewards, so if you have a card like the Chase Sapphire Preferred or Chase Sapphire Reserve, you can boost your United MileagePlus balance.

Then, add your other cities

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Destination one will be the first destination on your trip. Then, destination two will be your Excursionist Perk flight within the same region as your first destination. Then, destination three will be your flight home from your excursion city.

Then, enter your dates and hit 'search'

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Choose your first departing flight like you normally would.

The second flight is where the magic happens

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See where it says "zero miles?" That's the Excursionist Perk at work, and it only shows up at this step. Taxes are still required, as with any other award booking, but it's hard to find fault with a zero-mile flight.

Pick your third flight, and you're almost done

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Finalize your choices, because you just got three flights for the mileage price of two

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Fares to and from Europe from the United States were 30,000 miles each way in this case.

That's three flights within Europe for $131.53 and 60,000 miles

You can currently earn 40,000 bonus miles if you open the United Explorer Card and spend $2,000 in the first three months. So for me, this flight was basically just a perk of opening the card and putting some spending on it.

The Excursionist Perk got me here ...

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And here ...

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That same flight from Athens to Rome on the same date would have cost $163 if booked without award miles.

Another benefit? If the flights are in business class, your Excursionist Perk flight will be in the same class

United says that your Excursionist Perk flight will be in the same or a lower class, depending on availability.

It's possible to add more than three cities to your itinerary, but only one will be free

But, hey, one nearly free leg is better than paying for all three, right? The flights don't have to be in and out of the same cities, giving you more options to explore.

Here's how it works with a more complex itinerary to Australia and New Zealand

As both Australia and New Zealand are in the same region, the Excursionist Perk will work on flights there.

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This time, we'll try flying into Auckland, and then go down to Christchurch, New Zealand either by a separately booked cheap flight or a road trip. Then, the Excursionist Perk will kick in for a nearly free flight to Sydney, Australia before heading to Melbourne, and then back home.

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The flight between Christchurch and Sydney would cost well over $1,000 without this perk

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It worked, giving me three flights to, from, and within the same region for 80,000 miles

United's typical mileage needed for Australia is 40,000 miles each way.

Liz Knueven/Business Insider

That's a lot of adventure for $80,000 miles and $147.

This perk is truly a hidden gem of United's MileagePlus program, and I couldn't be happier that I found it.

It's unclear what will happen to this perk come United's award program changes in November. But, for the next few months at least, it's a tried-and-true, low-cost way to get more from your vacation.

Click here to learn more about the Chase Sapphire Preferred from Business Insider's partner The Points Guy »

Click here to learn more about the United Explorer Card from Business Insider's partner The Points Guy »

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