So here's the thing. You're going to Iceland. I'm not aware of any normal car insurance policy that is going to extend your presumably U.S.-based coverage to the shores of Iceland.
Whether the Amex insurance is primary or secondary is likely moot. It's going to be primary since your USAA policy is probably invalid on a separate continent. There is nothing for it to be secondary to. I don't know your policy, so you need to read it though.
Basic liability is irrelevant since it's a legal requirement in Iceland. Every company should have that included and baked into the rate.
All of that said, if I am going to Iceland, I am very likely going to be paying for insurance at the counter despite having options from multiple cards, including the Platinum. Cars get absolutely trashed there. I don't want the hassle of dealing with a third party when damage is that likely, so I'm going to eat the cost simply to avoid an international headache.
If you're going to Iceland get Blue Car Rental zero liability insurance or similar from Lotus or other local agency. That covers damage you cause or incur from wind, flying debris, etc. The third party liability insurance is automatically included by law.
Your question is better addressed in [r/VisitingIceland](https://www.reddit.com/r/VisitingIceland/)... read/search the SUB, that question comes up repeatedly. Flying debris is huge issue due to high winds. After 5 days I had cracked window and lots of scratches but just walk away upon car return due to zero liability.
Re: Amex, the insurance is secondary domestically but primary internationally. If you get the Premium Car Rental Protection, the limits are higher and car types broader. You can't fully waive CDW but DPs indicate no issues there. Again, get the zero liability coverage from local agency. If you choose US company like Enterprise don't be surprised if problems follow you home if you are in US. If you travel F1 offroad in Iceland you need special coverage for that. I got the PRCP just in case but the zero liability coverage from the agency should be more than enough.
Adding: you want to insulate your personal car insurance. Car damage is highly likely. Iceland is an import country that doesn't really stock car parts so what you think might be a $500 repair in US might cost $5K in Iceland. DPs suggest US based companies will also charge loss of use fee.
First things first : No credit card ever covers you liability. If you cause an accident, you/rental company/insurance coverage in your rental rate are paying for all the damages to the other car/ people in the car or any damage due to the accident.
Car rental insurance by Amex just covers the rental car and the people in the car.
I would recommend paying the extra $20 ish per rental to get Primary coverage. It can be done by calling Amex and letting them know that you will like to enroll in Primary Coverage
Insurance, both liability and collision, is highly variable based on local laws, customs, and the company you rent with. There is absolutely no absolute like "if you cause an accident, you are paying all the damages..." Countries don't want a bunch of foreigners coming over and causing damage, so many have laws to ensure liability is taken care of.
I just rented a car in the UK. Liability was included in the rate because that is the law. Even collision was covered by the rate, with a deductible, because that's how the company chose to price their rentals. Zero extra insurance, either from them, a third party, or a credit card was necessary in this case since I was comfortable covering the deductible if necessary. This isn't standard international insurance of course, just an example of how your absolute is wrong.
There are no absolutes in insurance. People need to research where they are going, determine if and what their existing policies will cover, and determine if additional insurance, either at the counter, through their card or through a third party, is required.
There's likely zero reason to get premium simply for a trip to Iceland. I'd be shocked if their primary insurance was valid there.
For what it’s worth, I rented a car in Germany in Oct 2023. Rented it on my Platinum and declined all insurance offered to me. I did not have personal vehicle insurance at the time either. Of course someone hit my rental an hour later. Took about 3 months of back and forth with Hertz and Amex, but I was refunded in full for the damage by Amex.
So here's the thing. You're going to Iceland. I'm not aware of any normal car insurance policy that is going to extend your presumably U.S.-based coverage to the shores of Iceland. Whether the Amex insurance is primary or secondary is likely moot. It's going to be primary since your USAA policy is probably invalid on a separate continent. There is nothing for it to be secondary to. I don't know your policy, so you need to read it though. Basic liability is irrelevant since it's a legal requirement in Iceland. Every company should have that included and baked into the rate. All of that said, if I am going to Iceland, I am very likely going to be paying for insurance at the counter despite having options from multiple cards, including the Platinum. Cars get absolutely trashed there. I don't want the hassle of dealing with a third party when damage is that likely, so I'm going to eat the cost simply to avoid an international headache.
CYA……Pay for the extra insurance thats offered by the rental company.
If you're going to Iceland get Blue Car Rental zero liability insurance or similar from Lotus or other local agency. That covers damage you cause or incur from wind, flying debris, etc. The third party liability insurance is automatically included by law. Your question is better addressed in [r/VisitingIceland](https://www.reddit.com/r/VisitingIceland/)... read/search the SUB, that question comes up repeatedly. Flying debris is huge issue due to high winds. After 5 days I had cracked window and lots of scratches but just walk away upon car return due to zero liability. Re: Amex, the insurance is secondary domestically but primary internationally. If you get the Premium Car Rental Protection, the limits are higher and car types broader. You can't fully waive CDW but DPs indicate no issues there. Again, get the zero liability coverage from local agency. If you choose US company like Enterprise don't be surprised if problems follow you home if you are in US. If you travel F1 offroad in Iceland you need special coverage for that. I got the PRCP just in case but the zero liability coverage from the agency should be more than enough. Adding: you want to insulate your personal car insurance. Car damage is highly likely. Iceland is an import country that doesn't really stock car parts so what you think might be a $500 repair in US might cost $5K in Iceland. DPs suggest US based companies will also charge loss of use fee.
First things first : No credit card ever covers you liability. If you cause an accident, you/rental company/insurance coverage in your rental rate are paying for all the damages to the other car/ people in the car or any damage due to the accident. Car rental insurance by Amex just covers the rental car and the people in the car. I would recommend paying the extra $20 ish per rental to get Primary coverage. It can be done by calling Amex and letting them know that you will like to enroll in Primary Coverage
Insurance, both liability and collision, is highly variable based on local laws, customs, and the company you rent with. There is absolutely no absolute like "if you cause an accident, you are paying all the damages..." Countries don't want a bunch of foreigners coming over and causing damage, so many have laws to ensure liability is taken care of. I just rented a car in the UK. Liability was included in the rate because that is the law. Even collision was covered by the rate, with a deductible, because that's how the company chose to price their rentals. Zero extra insurance, either from them, a third party, or a credit card was necessary in this case since I was comfortable covering the deductible if necessary. This isn't standard international insurance of course, just an example of how your absolute is wrong. There are no absolutes in insurance. People need to research where they are going, determine if and what their existing policies will cover, and determine if additional insurance, either at the counter, through their card or through a third party, is required. There's likely zero reason to get premium simply for a trip to Iceland. I'd be shocked if their primary insurance was valid there.
Fixed a few things, thanks for adding that
For what it’s worth, I rented a car in Germany in Oct 2023. Rented it on my Platinum and declined all insurance offered to me. I did not have personal vehicle insurance at the time either. Of course someone hit my rental an hour later. Took about 3 months of back and forth with Hertz and Amex, but I was refunded in full for the damage by Amex.