HomeAgain sells more than one type of microchip, and whether yours is ISO compatible depends on which one your pet has. The standard US-market HomeAgain chip is not ISO compliant. HomeAgain's ISO-format chips are. This distinction matters for international travel, and the original article on this page got it wrong. Here is the accurate picture.
A microchip qualifies as ISO compliant when it meets both of the following: it operates at 134.2 kHz, and it carries a 15-digit numeric ID conforming to ISO 11784/11785. Both conditions must be met. A 15-digit chip at 125 kHz does not qualify. A chip operating at 134.2 kHz without the correct ID structure does not qualify either.
The standard US-market HomeAgain chip operates at 125 kHz and carries a 10-character alphanumeric ID. Per WSAVA microchip identification guidelines, this chip does not meet ISO 11784/11785 standards and is not ISO compliant.
HomeAgain also manufactures ISO-format chips, including their WorldChip, which operate at 134.2 kHz and carry a 15-digit numeric ID. These are ISO compliant and accepted for international travel.
The chip brand alone does not tell you which type your pet has. You need to confirm the specific product.
The most reliable method is a two-step check. First, have your vet scan the chip and note the ID. If the number is 15 digits numeric, that is consistent with ISO format. If it is 10 characters or alphanumeric, it is the non-ISO standard chip. Second, confirm the frequency in the product documentation for that specific chip. The frequency must be 134.2 kHz for ISO compliance. If you are unsure, your vet can help confirm the chip model. You can also cross-reference the manufacturer code against the International Committee for Animal Recording (ICAR) registry at icar.org.
If your pet has the standard 125 kHz HomeAgain chip, you have two practical options for international travel.
The first is to travel with a compatible scanner. APHIS guidance for pets with non-ISO chips is to bring a scanner that can read your chip's frequency. Universal scanners capable of reading 125 kHz, 128 kHz, and 134.2 kHz chips are available for purchase. This keeps your existing documentation chain intact and avoids any additional procedures.
The second option is to have a second ISO-compliant chip implanted alongside the existing one. The original chip does not need to be removed. If you go this route, both chip numbers must appear on every piece of veterinary documentation going forward. There is a critical timing requirement: the ISO chip must be implanted and confirmed readable before the rabies vaccination is administered, or the vaccination will not count toward destination country requirements. If a new rabies vaccine is needed, the standard 21-day post-vaccination wait restarts from that date. Confirm with your vet whether a second chip is actually required for your specific destination before scheduling any procedures.
EU entry requires a microchip operating at 134.2 kHz that meets ISO 11784/11785. The standard US HomeAgain chip does not meet this requirement. HomeAgain's ISO-format chips do. If you are traveling to an EU country and your pet has the standard HomeAgain chip, work through the options above before finalizing travel plans.
For a full breakdown of EU microchip requirements, including the timing rules around microchipping and rabies vaccination, see our EU microchip compliance guide. For the same analysis applied to AVID chips, see our AVID microchip guide.
If you want help confirming your pet's microchip status before booking travel, our team can walk you through it.