A bonus that lands on day one of a genuinely good promo month

Transfer bonuses come around often enough that most of them aren't worth much attention. This one is different, because of timing. On October 1, two things went live simultaneously: American Express began a 25% transfer bonus to Air France-KLM Flying Blue, running through October 31, 2026 — and Flying Blue published its October Promo Rewards list, which happens to include business class between Seattle and Europe at 45,000 miles and Mexico City to Europe at 45,000 miles. Stack the two and a transatlantic business seat prices at 36,000 Membership Rewards points. That is an absurd number.

The mechanics are simple. Amex Membership Rewards normally transfer to Flying Blue at 1:1. Until 11:59 p.m. Mountain Time on October 31, every 1,000 points you move becomes 1,250 Flying Blue miles. The bonus is automatic — no registration, no opt-in — and it applies an unlimited number of times, in transfers of 1,000 to 999,000 points. Transfers are usually instant, though Amex says to allow up to 48 hours. As always, transfers are one-way: once points leave Membership Rewards, they don't come back.

How good is 25%? About as good as this gets

This matters because 25% is effectively the ceiling on this particular corridor. Amex has run bonuses to Flying Blue more than a dozen times over the past several years, and the largest we've seen is 30% — a one-off in August 2021 that was offered from Flying Blue's side. Since then, the pattern has settled: 20 to 25%, roughly once or twice a year. The last one ran in June 2026 at 25%, which means anyone who passed then gets another shot almost immediately. You won't find a 40% Amex-to-Flying Blue bonus sitting in the wings — the program just doesn't do it.

Worth noting for context: other transfer bonuses are running concurrently, and they're worth a glance before you commit. Rove Miles is offering a 40% bonus to Flying Blue through October 31 — mathematically better, but only useful if you hold Rove's currency. Amex is also running a 20% bonus to Aeromexico ClubPremier through October 30. And Bilt's Rent Day on October 1 is offering up to 200% to Hilton for Platinum members. If you're flush with Amex points specifically, though, Flying Blue is where the month's value sits.

The worked examples

Here's what the transfer math does to Flying Blue's current sweet spots:

• Business class, Seattle to Europe, on October Promo Rewards: 45,000 Flying Blue miles, currently listed for travel through March 31, 2027. With the bonus, that's 36,000 Amex points. For perspective, that's roughly what some programs charge for a domestic business seat, except this one crosses the Atlantic on Air France.
• Business class, Mexico City to Europe: 45,000 miles on KLM metal, also a 36,000-point proposition with the bonus.
• Standard business class, North America to Europe: 60,000 miles one-way. That's 48,000 Amex points. Current award searches are showing that 60,000-mile floor on Air France flights to Paris from Atlanta, Boston, Chicago, Houston, Newark, New York, Raleigh-Durham, San Francisco, Seattle, and Washington, D.C., with travel dates stretching into July 2027. Up to nine business seats on some dates — availability this generous is the exception, not the rule.
• Economy promo to Europe: the 18,750-mile discounted economy rate on routes like Raleigh/Durham, Houston, Boston, Chicago, Toronto, and Montreal to Europe costs just 15,000 Amex points.
• KLM business class to South Africa: 115,000 Flying Blue miles for U.S. to Cape Town via Amsterdam — 92,000 Amex points with the bonus. That's a route where cash business fares routinely clear $5,000.

The 60,000-mile question, honestly answered

One caveat deserves a full paragraph, because the game changed on September 8, 2026, when Flying Blue split award tickets into Light, Standard, and Flex fares. The 60,000-mile business price you see now is a Light fare: one checked bag, no lounge access, no changes or refunds, no advance seat selection. The ticket that actually matches what 60,000 miles bought before the change is now Standard, at 75,000 miles — a 25% increase dressed up as choice.

So be clear-eyed about what you're buying. At 60,000 miles with the transfer bonus, you're effectively paying 48,000 Amex points for a no-frills business seat. The seat itself is the same lie-flat product; what's missing is lounge access and flexibility. For a trip you're confident about taking, Light is fine — 48,000 points for a $5,300 ticket is over 10 cents of value per point even after roughly $340 in taxes and surcharges. If you might need to change dates, price Standard instead: 75,000 miles, or 60,000 Amex points with the bonus. Either way, the bonus softens the fare-structure sting, but it doesn't erase it.

What to do before you transfer

Three rules, as always with speculative transfers.

First: find the seat before you move the points. Transfers are irreversible and typically instant, which means you can search Flying Blue availability, find the dates you want, and then transfer exactly what you need. The month's Promo Rewards are valid for booking through October 31 for travel through March 31, 2027, so there's real runway — but the promo-priced inventory (especially the 45,000-mile Seattle business seats) goes first.

Second: watch the surcharge line. Flying Blue passes through Air France and KLM carrier surcharges, and on transatlantic business class that means roughly $260–$340 out of pocket per direction. That's a meaningful add-on, and on cheap economy awards it can erase the deal entirely. On business class it doesn't kill the math — 48,000 points plus $340 for a ticket selling for $5,300-plus is still one of the best ratios in the hobby — but know the full price before you commit.

Third: respect the expiration clock. Flying Blue miles expire after 24 months of inactivity, and a transfer from Amex doesn't reliably count as qualifying activity. Do not park 200,000 points in Flying Blue "for someday." Move points with a trip attached — ideally a trip you've already confirmed has award space — and you'll never think about expiration.

The bottom line

A 25% bonus to Flying Blue is the program's standard ceiling, it's good through Halloween, and it arrives in a month when Flying Blue's own promo calendar is offering transatlantic business class at 45,000 miles. That combination produces something rare: a business-class seat across the Atlantic for 36,000 points from a major transferable currency. If you hold Amex points and have any thought of visiting Europe between now and next spring, this is the month to check the award calendar before you do anything else.