Getting a cat into a carrier without a fight

Most cats do not object to the carrier. They object to the carrier appearing five minutes before a car journey.
A cat who only sees the carrier on the way to the vet learns exactly what it means. The wrestling match that follows is not stubbornness — it is a reasonable response to a box that has never once led anywhere good.
Leave it out
The single change that makes the most difference is to stop putting the carrier away. Left open in a corner of a room the cat already uses, with a familiar blanket inside, it stops being an event and becomes furniture. Feeding treats near it, then in it, does the rest. This takes weeks rather than days, so it is worth starting long before there is an appointment to get to.
Pick a carrier that comes apart
A hard carrier whose top half unclips is far easier on everybody. A cat who will not walk in can be lowered in, and — more usefully — a nervous cat can be examined while still sitting in the bottom half rather than being poured out of a small door.
On the day
- Put the blanket in that already smells of home rather than a freshly washed one.
- Shut the cat in one room first. Chasing one around a house before a trip undoes the preparation.
- Cover the carrier with a towel in the car. Less to look at means less to worry about.
- Belt the carrier in, or wedge it in a footwell, so it is not sliding about on corners.
If it still goes badly
Some cats are simply not going to be talked into it, and forcing the issue can make the next attempt harder still. It is worth saying so when booking — a practice can plan around a cat who arrives upset, and there are approaches worth discussing with your vet for cats who find the trip genuinely distressing.