If you pay suppliers in more than one country, you've probably run into a confusing mix of acronyms on invoices and payment forms — ACH, SEPA, Faster Payments, SWIFT, BACS, CHAPS, and more. Each of these is a payment rail: the underlying network that actually moves money between banks. None of them are interchangeable, and using the wrong one (or assuming a domestic rail will work internationally) is one of the most common causes of payment delays for businesses paying suppliers abroad.
This guide breaks down the major rails, what region they belong to, and how they actually compare on speed and cost.
The big picture: domestic rails vs international wires
Almost every country has its own domestic payment rail — a network built to move money quickly and cheaply between banks within that country or region. SWIFT, by contrast, is the global messaging network used for international wires when no shared domestic rail connects the sender and receiver. The general rule: if you're paying within a single country or shared currency zone, you can often use a fast, cheap local rail. If you're paying across that boundary, you're usually looking at a SWIFT wire, with all the extra cost and time that involves.
SEPA — the Eurozone's domestic rail
SEPA (Single Euro Payments Area) covers 36 countries across Europe, including all Eurozone members plus several others that have opted in. It allows euro-denominated payments to move between any two SEPA countries as if they were domestic transfers, using just the recipient's IBAN.
Speed: SEPA Credit Transfer typically settles within one business day. SEPA Instant Credit Transfer, an increasingly widely supported variant, settles within seconds, 24/7.
Cost: Usually low or free, since it's treated as a domestic-equivalent payment rather than an international wire.
Key requirement: The payment must be in euros, and both the sending and receiving bank must be within the SEPA zone.
This is why paying a supplier in Germany, France, or the Netherlands in euros is often far cheaper and faster than people expect — it's not actually an "international" payment from the network's point of view, even though it's crossing a border.
Faster Payments — the UK's domestic rail
Faster Payments is the UK's real-time domestic payment system, covering GBP transfers between UK bank accounts using a sort code and account number.
Speed: Typically seconds to a couple of hours, available 24/7 including weekends and holidays.
Cost: Usually free or very low cost for standard transfers.
Key requirement: Both sender and receiver need a UK bank account, and the payment must be in GBP.
If you're paying a UK supplier from a UK account, Faster Payments is almost certainly what your bank uses by default. It cannot be used to send GBP from outside the UK — that requires a SWIFT wire instead.
ACH — the United States' domestic rail
ACH (Automated Clearing House) is the batch-based system used for the vast majority of routine domestic US payments, identified by a 9-digit routing number and an account number.
Speed: Typically 1–3 business days for standard ACH, though a same-day ACH option exists for an additional fee.
Cost: Usually low or free — significantly cheaper than a wire for domestic US payments.
Key requirement: Both sender and receiver need a US bank account. ACH is domestic-only and cannot be used for international transfers.
For larger or more time-sensitive domestic US payments, a same-day wire transfer (via Fedwire or CHIPS) is used instead of ACH, at a higher cost.
SWIFT — the global network for everything else
SWIFT isn't a single payment rail in the same sense as the others — it's a messaging network that banks around the world use to instruct each other to move money, and it's what underpins most traditional international wire transfers when no shared regional rail applies.
Speed: Typically 1–5 business days, depending on how many intermediary banks the payment passes through.
Cost: Usually the most expensive option, often involving fees from the sending bank, intermediary banks, and sometimes the receiving bank too — which is part of why the amount that arrives can be slightly less than the amount sent.
Key requirement: A SWIFT/BIC code for the receiving bank, plus either an IBAN or local account details depending on the destination country. See our SWIFT/BIC guide for more detail on how these codes work.
SWIFT is the fallback that works almost anywhere, which is exactly why it's slower and pricier than the regional alternatives above — it has to accommodate far more variation in banking systems worldwide.
Other notable regional rails
A few more worth knowing if you pay suppliers more broadly:
Interac e-Transfer (Canada) — a widely used domestic system for moving CAD between Canadian banks, typically near-instant for personal and small business payments.
NPP / PayID (Australia) — Australia's New Payments Platform allows near-instant domestic AUD transfers, often using a simpler PayID (like an email or phone number) instead of full bank details.
FPS (Hong Kong) and PayNow (Singapore) — fast domestic real-time payment systems in their respective markets, increasingly linked to each other for faster cross-border transfers between the two.
UPI (India) — an extremely widely adopted real-time domestic payment system, though primarily used for personal and retail payments rather than commercial international invoicing.
A quick comparison
| Rail | Region | Typical speed | Typical cost | International? |
|---|---|---|---|---|
| SEPA | Eurozone (36 countries) | Seconds–1 day | Low/free | Within zone only |
| Faster Payments | UK | Seconds–hours | Low/free | UK domestic only |
| ACH | United States | 1–3 days | Low/free | US domestic only |
| SWIFT | Global | 1–5 days | Higher, multiple fees possible | Yes, by design |
What this means for paying suppliers abroad
If your supplier is within the same regional payment zone you're paying from — both in the Eurozone, both in the UK, both in the US — check whether a domestic-equivalent rail like SEPA, Faster Payments, or ACH applies before defaulting to an international wire. It's often faster and meaningfully cheaper. If you're paying across regions (say, a UK business paying a US supplier in dollars), a SWIFT wire is typically unavoidable, and it's worth budgeting for both the transfer fee and a few days of processing time.
The part that matters just as much: timing the conversion
Choosing the right payment rail gets your money there efficiently. But for any invoice priced in a foreign currency, the bigger cost factor is often when you convert, not how the payment is routed. A multi-day SWIFT wire combined with a poorly timed conversion can cost far more than the wire fee itself.