UPDATE | A new United Airlines 'buy miles' promotion is underway, giving bonuses of up to 75% on MileagePlus purchases through 2:59pm (Sydney time) on July 4 2017 which can then be redeemed for travel on Air Canada, Singapore Airlines, Thai Airways, United Airlines and other Star Alliance members.

Buying 5,000-24,000 miles comes with a 35% bonus, while buying 25,000-85,000 miles attracts the full 75% boost.

Your best option for buying in bulk? Pick up 80,000 miles (rather than the full 85,000 miles) at a cost of US$3,010 (A$3,975), delivered with 60,000 bonus miles on top (your 75% bonus) for a total haul of 140,000 United miles.

That's precisely enough for a return first class trip from Sydney to Bangkok, Singapore or Hong Kong with Thai Airways (80,000 miles), plus a return business class trip to the same destinations with Thai Airways or Singapore Airlines (60,000 miles): two trips up the front for less than you'd pay for one at retail prices, although be prepared to cover taxes and fees of $50-100 per flight when booking using real money.

Or, if you're happy to fly business class on both return flights, you can save some cash by buying a smaller 69,000 miles instead, with 51,750 bonus miles on the side at a total cost of US$2,596 (A$3,429): churning out 120,750 miles in total: more than enough for those two business class return trips.

Just a tip: while business class redemptions are indeed possible on selected Singapore Airlines flights (telephone booking required), look to Thai Airways for first class bookings between Australia and Asia as these aren't available via SQ.

The article below, while written around a previous 25-40% discount promotion, explains more about the process of buying and using United MileagePlus Miles to book flights across the Star Alliance.

PREVIOUS | Want to fly from Australia to Bangkok in Thai Airways' first class cabin for $2,000? How about business class to Singapore with Singapore Airlines for around $1,600, or Sydney to New York for less than $4,000?

Those are some of the amazing deals you can line up courtesy of United Airlines' latest promotional sale of MileagePlus frequent flyer miles.

UA is putting MileagePlus points on the block at massively discounted rates which, when redeemed on award flights with UA or any of its Star Alliance partners, deliver a saving of between 50-70% over regular ticket prices.

But you'll have to move fast: United's promotion closes at 5pm on Tuesday February 18, EST (that's midnight February 17 in UA's home base of Chicago).

So what’s the deal?

Purchase anywhere from 15,000 to 39,000 United miles and you’ll receive a 25% cash discount on the usual asking price.

Pony up for 40,000 to 150,000 miles and the savings escalate to 40%.

(And as UA won't let you buy more than 150,000 miles per calendar year, you may as well max out and grab all of those points while you can.)

Those rates are good enough on their own, but when coupled with the recent Mileage Plus redemption rate improvements for Aussies heading abroad you'll land some incredible discounts at the pointy end – if you know where to look, of course!

While you'll still need to cough up a reasonably small amount for taxes and surcharges, the overall savings from bulk-buying  MileagePlus miles under this promotion speak for themselves.

Here are our five top picks for using your haul of newly-acquired UA miles.

Australia to North America

United Airlines offers one-way redemptions from Australia to anywhere in the United States for 70,000 Mileage Plus miles in business class and 80,000 in first class.

Although that annual purchase cap of 150,000 miles prevents you from buying enough miles for a return journey in first class, you can pocket 140,000 miles for around US$3,160 – enough for a return trip between Sydney and New York in UA business class (below).

How do those prices stack up against United's regular pricing? Flying that same Sydney-New York business class return trip in May would set you back A$5,558, which is just shy of US$5,000 – so you'll pocket a cool $2,000 by trading your cash for miles and redeeming them for the same flight.

Also read: United upgrades Sydney, Melbourne flights to Boeing 777s in April

Within the USA

International-grade travel between Los Angeles or San Francisco and New York is also yours for a song on United's transcontinental 'p.s' flights, which boast fully lie-flat seats and 16 inch video screens in UA's BusinessFirst cabin (below).

One-way ‘Saver Award’ redemptions are priced at 25,000 miles in BusinessFirst, so under the MileagePlus promotion the 50,000 miles needed for a return flight would cost US$1,129.

Compared to United's asking price of US$3,572 for a BusinessFirst fare in May, that’s a saving of nearly 70%!

If you'd rather conserve those miles for the long trek between Australia and the USA, you could book an economy seat on the same UA service for 12,500 miles.

Of course, you've got hundreds of other domestic UA routes to choose from. If you regularly do business in the USA we'd suggest seriously stocking up on MileagePlus points ahead of your next trips.

Also read: United Airlines set for US transcon turf war with American, JetBlue, Delta

Australia to Singapore

Closer to home you can use your MileagePlus miles to book some amazing fares with UA partner Singapore Airlines.

A one-way trip from Australia to Singapore with Singapore Airlines is costed at 17,500 miles in economy and 30,000 in business – though you won't be able to luxe it up in a first class suite on SQ's Airbus A380, as these redemptions aren't typically available to MileagePlus users.

As such, US$1,354 sees you settled very comfortably in business class.

These same flights would usually cost around A$4,262 in business on a return journey, using dates in May.

The only catch is that you'll need to call United Airlines to make these particular redemptions, as SQ award seats are not available online.

Australia to Thailand

The same mileage purchase and redemption rates above apply for business class flights between Australia and Thailand.

If you'd rather stump for first class, that's 40,000 miles each way, so US$1,806 would buy enough miles for a return journey in first class.

These same flights would usually cost around AU$5,605 in first class and AU$4,262 in business (using dates in May) – again, a considerable saving over the retail fare.

Based on travel in May, first class on Thai Airways from Sydney to Bangkok would usually set you back A$5,708, with business class (below) hitting A$3,997.

The cost to you if you splurge right now on discounted MileagePlus points? Around A$2,000 for first class return and $1,500 in business class.

Australia to South Africa

Star Alliance member South African Airways flies daily between Perth and Johannesburg, with one-way redemptions available for 85,000 MileagePlus miles in business class and 50,000 miles in economy.

Although you won’t be able to buy enough miles for a round trip in business, this might be an option to consider if you already have at least 20,000 miles in the kitty.

On that basis you’ll be able to grow your balance to 170,000 miles for US$3,386 – enough to take that business class trip. With the cheapest return business class fare showing at AU$5,052 in May, it’s a great find.

But before you buy...

As with any reward program, award availability is never guaranteed on specific flights. It tends to help if you’re a little flexible on dates or have the time to take an indirect flight.

To sidestep this, United’s website can be used to search for flight awards on specific dates before you have the necessary number of miles sitting in your account – so if you can only travel on a particular date, you’ll be able to check that an award is available before shelling out for the miles.

Also, if you’re aiming to attain or retain your Star Alliance Gold or Silver status, be mindful that flights booked with miles won’t count towards your Premier qualifying miles or qualifying segments under the Mileage Plus program.

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