The Amex to Flying Blue 25% Bonus Stacks With October Promo Rewards: Business Class to Europe for 36,000 Points (2026 Guide)

Business class to Europe for 36,000 Amex points. One-way.

That is the number you get when two live offers land on the same award. Amex is running a 25% transfer bonus to Flying Blue through October 31, and Flying Blue’s October Promo Rewards cut select Europe routes to 45,000 miles in business class. Multiply the two and a Seattle to Europe business seat that would normally cost 60,000 Amex points costs 36,000.

I covered the bonus itself earlier this month. This post is about the stack: what the October Promo Rewards actually are, the exact routes where the two offers overlap, and the booking order that keeps your points safe. Here is the math, the route list, the three-step playbook, and the Light-fare catch that decides whether the cheapest price is the one you actually want.

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TL;DR

Two offers, one award, both ending October 31, 2026:

• Offer 1: Amex Membership Rewards transfer to Flying Blue with a 25% bonus. 1,000 Amex points become 1,250 Flying Blue miles. No registration, built into the transfer ratio.
• Offer 2: Flying Blue October Promo Rewards discount select routes by 25%, including business class between Europe and Seattle or Mexico City at 45,000 miles one-way. Book by October 31, travel through March 31, 2027.

Stacked, the promo business awards cost 36,000 Amex points one-way instead of 60,000. The math with and without the bonus:

The one rule for the whole post: find the promo seat on your dates first, then transfer. Transfers are one-way, and the bonus cannot rescue points you moved for a seat that was never there.

The two offers, separately

The transfer bonus. From October 1 through October 31, 2026 (ending 11:59 p.m. MT), Amex Membership Rewards transfer to Air France-KLM Flying Blue at 1,000 points to 1,250 miles instead of the usual 1:1. The bonus is baked into the transfer ratio on Amex’s transfer screen, so there is nothing to register for. Minimum 1,000 points, maximum 999,000, in 1,000-point increments. Amex says transfers are normally instant, but allow up to 48 hours. One point worth being precise about: this is a bonus on an existing partner. Amex and Flying Blue have transferred 1:1 for years. Nothing about the partnership is new; only the ratio is, and only through October 31.

The Promo Rewards. Flying Blue runs a monthly award sale that discounts select routes, usually by 25%. Each month brings a new route list, and October’s is unusually generous because business class made the long-haul list. The terms: book by October 31, 2026, and complete travel by March 31, 2027. The advertised prices are “starting at” minimums, not guaranteed rates on every date, and they now apply to the restrictive Light fare (more on that below). A handful of routes are reserved for Flying Blue Extra subscribers, a paid membership that starts at 379 euros a year.

Here are the US routes on the October list:

The headline number is the Seattle and Mexico City business promo: 45,000 Flying Blue miles one-way. Divide by the 1.25 bonus ratio and you get 36,000 Amex points, and that is the whole stack.

The stack math, worked out

A 25% transfer bonus means you need 20% fewer Amex points for the same award. The formula is simple: Flying Blue miles needed, divided by 1.25, rounded up to the next 1,000 (Amex only transfers in 1,000-point increments).

Example 1: Seattle to Europe, business class, promo Light fare. 45,000 Flying Blue miles. With the bonus: 36,000 Amex points. At the standard 1:1: 45,000 Amex points. You save 9,000 Amex points per person, per direction. For two people round-trip, that is 36,000 Amex points saved, which is most of another one-way business seat.

Example 2: Paris to the US, business class, Light fare (no promo). 60,000 Flying Blue miles. With the bonus: 48,000 Amex points. At 1:1: 60,000. You save 12,000 Amex points, which is the number I worked through in the bonus-only post earlier this month.

Example 3: Boston to Europe, economy, promo fare. 18,750 Flying Blue miles. With the bonus: 15,000 Amex points. At 1:1: 18,750, which rounds to 19,000 in practice because of the 1,000-point transfer increments. You save about 4,000 Amex points per person.

Here is the full cost picture for the headline example:

The taxes and fees are the part people underestimate. Flying Blue business awards to Europe carry several hundred dollars in cash charges per person, one-way, and the cash charge is identical whether you book the Light or the Standard fare. On the 45,000-mile Seattle and Mexico City promos, route estimates put it near 388 euros one-way. A standard Paris business award runs closer to 527 euros. Budget for the cash before you move a single point.

How to book it, in order

The order matters more than the math. Get it backwards and you own 45,000 Flying Blue miles with no seat attached.

1. Search Flying Blue for your dates and confirm the promo price. Promo seats are limited, and the listed prices are “starting at” minimums. If your dates price higher, the stack still works, but the headline number does not. Only proceed when you can see the award you want at a price you accept.
2. Note the fare type and the cash charges. The search results now show Light, Standard, and Flex. Write down the mileage price and the exact taxes and fees before you touch Amex.
3. Transfer from Amex. You need a Flying Blue account first; Amex requires enrollment before the transfer option appears. The 25% bonus is built into the transfer ratio on the screen, so confirm it shows 1,250 miles per 1,000 points before you submit. Transfer only what the award needs, in 1,000-point increments. Transfers are usually instant, but allow up to 48 hours, and you cannot book until the miles land.
4. Book before October 31. The bonus and the promo booking window end the same night. Your travel can be as late as March 31, 2027, but the ticket must be issued by October 31, 2026.

The honest caveats

A point worth being honest about, because it trips people up: since September 8, Flying Blue’s cheapest awards are Light fares, and a Light business ticket is not the business class award you remember booking. Here is what each tier buys on a transatlantic business award, using Paris as the example:

On paper, the 45,000-mile promo price looks like the whole story. In practice, the fare type is half the purchase. A Light business award gets you the seat and one checked bag, but no lounge, no changes, no refunds, and paid seat selection. If your dates are firm and you travel light, Light is genuinely the cheapest business class across the Atlantic right now. If there is any chance your plans move, price the Standard fare before you fall in love with the Light number.

The rest of the fine print, briefly: promo seats are limited and the 45,000-mile figure is a floor, not a promise. Flying Blue miles expire 24 months after your last account activity, and a transfer resets the clock, so do not move points speculatively for a trip you have not priced. And the new fare families only apply to Air France and KLM operated flights; partner-operated awards keep their old structure.

My take

The stack is real, and it is the cheapest business class to Europe I have seen this month. But the smartest use of the bonus is not the headline. Look at the TL;DR table again: the 56,250-mile promo Standard fare for Seattle, with the 25% bonus, costs 45,000 Amex points. That is exactly what the 45,000-mile promo Light fare costs without the bonus. So the bonus effectively buys you the flexible, lounge-included fare for the price of the restricted one.

That is the transfer worth making. Do not top up speculatively, do not move points for a seat you have not found, and do not book Light to save miles on a trip you might need to change. Find the seat, confirm the fare, move exactly what you need, and book before October 31.

Frequently Asked Questions

Do I need a Flying Blue Extra subscription to book these promo awards?

No, for most of them. The Seattle, Mexico City, Boston, Houston, Raleigh/Durham, Miami, Chicago, Las Vegas, and Austin promos are open to all Flying Blue members. The Orlando and Cancun business promos at 45,000 miles are reserved for Flying Blue Extra subscribers, a paid membership starting at 379 euros a year. Do not buy the subscription for one award; the math only works if you fly these routes regularly.

How fast do Amex transfers to Flying Blue post?

Usually instantly, which is the speed that matters for holding a promo seat. Amex officially says to allow up to 48 hours, and you cannot book until the miles appear in your Flying Blue account. The 25% bonus is built into the transfer ratio, so confirm the screen shows 1,250 miles per 1,000 points before you submit. If the transfer hangs, do not fire a second one until the first resolves.

Can I change or cancel a Light business award?

No. Light awards allow no voluntary changes and no refunds, and that is the fare the promo prices are quoted on. If you need flexibility, book the Standard fare, which allows changes and refunds for a 70 euro fee per ticket. Tickets are also locked to the fare family at booking; you cannot upgrade a Light ticket to Standard later by paying the mileage difference.

How much are the taxes and fees on these awards?

Several hundred dollars per person, one-way, and they are the same cash amount on Light and Standard fares. Route estimates put the 45,000-mile Seattle and Mexico City promo business awards near 388 euros one-way; a standard Paris business award runs closer to 527 euros. Always price the exact cash charges on your dates before transferring, because the fees can erase the advantage over a cheap cash fare on shorter routes.

What happens after October 31?

The transfer bonus ends and the ratio returns to 1:1, and the October Promo Rewards booking window closes. Flying Blue publishes a new Promo Rewards list every month, so November will bring different routes, and there is no guarantee business class makes the list again. The stacking concept itself is evergreen: whenever a transfer bonus overlaps a promo award month, the same math applies.

The Bottom Line

A 25% transfer bonus plus a 25% award sale is the cheapest seat in the game, and October happens to have both pointed at the same Flying Blue awards. Business class between Europe and Seattle or Mexico City for 36,000 Amex points one-way is a genuinely good redemption, as long as you find the seat first, understand that the promo price buys the Light fare, and transfer only what the award needs. After October 31 the bonus is gone and the route list refreshes. Book what you need to book before then.

Related Reading: Amex to Flying Blue 25% Bonus: Paris Business for 48,000 Points · What Is a Credit Card Transfer Bonus? (And How to Actually Use One) · Do Airline Miles Expire? The 2026 Guide to Every Expiry Rule

Find the seat, move the points, and fly business to Europe for 36,000 Amex points before October 31.