Mentioned briefly in the Portuguese press, IUC (annual Road Tax) will become due In February each year, regardless of the vehicles month of registration. If over 100€, two payments can be made Feb/October

Yep! I am one of the lucky ones, My IUC is due middle of December so I pay the full amount for only 2 weeks and then I have to pay again in February for something I already paid. That should be illegal but I haven't seen anything that is going to stop it.

Regardless of when you pay, the tax is for the calendar year.

Diesel cars are bad; old diesels cars are very bad.

But the IUC on old diesel cars is really good.

Not sure what you mean? Under the old system I paid in December and that covered me for 12 months and then I paid again in December for the following 12 months.
Now I pay in the middle of December and it lasts for 2 weeks. I then have to pay in February for the whole of 2026, so basically I am paying twice for 2026.
Some you win some you lose. I think most people don't realise that they will be paying twice, the later you pay this year the more you are screwed!!!

Perhaps in the year of transition, the payment will be pro-rata and so nobody will lose out?

It should be but it is not unless people power makes them give in. I haven't seen any campaigns to get this sorted cos it seems to be being brought in under the radar and nobody really understands. They will when they have to pay again in February but it will be too late by then

Most won’t know about it until it happens. I have seen some comments online with locals but they haven’t quite sussed exactly what it means yet. It’s very hard trying to explain it to them but paying the IUC is paying for the year ahead, and if you’ve just paid it in January at your vehicle anniversary then again February that’s a kicker.
I have seen no evidence of a pro-rata payment but that would make sense,.. so I doubt that will happen.
Once it dawns on the many that they are in effect paying twice there will be more noise. Cries of CHEGA ring out! lol.😂

The new tax changes are that all cars will pay their tax in February for year 2026, payment can be split into 2 payments if the tax is over 100 euros. So if your car was registered in January then you will not be requested to pay for 2026 until February. If you are unlucky enough to have your car registered on the 31st December then you will have to pay the full amount for the 12 months and then again in February for 2026. I am almost the worst case as mine is due mid December.

They do appear to like changing laws and rules/regulations that always seems to kick the population in the balls here, sometimes when things work they're best left to work as intended, whoever came up with this plan should be demoted into a suitable position....

I suggest handing out senhas at the financas office when the machine is broken....

I can understand your viewpoint but liveaboard is correct - you are not paying 12 months in advance when you pay IUC. You are paying the amount due in the financial year, which runs from Jan 1 - Dec 31. So you'll be paying once in 2025 and once in 2026, regardless of the payment due date change.

Does that mean someone who first registers a new car say on 1 December has to pay a full year and then again in February the following year? In other words, the annual amount of IUC is payable whether one has the vehicle for 1 day or any period up to the full year?

That is my understanding.

Thanks. Come to think of it, that's how IMI works albeit payable the following year and charged to the registered owner as at 31 December.

That will be the new system in 2026, up till now you pay for 12 months from the registration date of your car so that you can legally driver on Portugal's roads for 12 months. Same as UK, you pay for 12 months from date of registration.

Are you certain? I must admit that was my original understanding but, upon reflection, I don't think that's how it works in PT. It's no different to how IMI is charged. Let's say you purchased a property in the middle of December 2025 and hence was the registered owner on 31 December 2025, you would be responsible for paying the IMI for the whole of 2025 even though you would have only owed it for 2 weeks. Fair or unfair, that's how it is done.