What is the best way to invest in Ireland-Domiciled S&P 500 ETFs?

Interactive brokers is good.

Hey there, you can actually use and of the online brokerages on the Seedly platform which are in this list here: https://seedly.sg/reviews/online-brokerages

I would say two of the more compeitive ones are FSM ONE and SAXO for a modern interface and also relatively lower charges for US stocks. (even though Ireland Domiciled)

However, thing to note is that some in the community often use Interactive Brokers as well (for accounts funded more than USD10k) so that's one which you can consider as well.

Cheers!

Interactive Brokers is the recommended broker due to its lower fees. However, I wonder if it is a good idea to set up a brand new broker account just to buy Ireland domiciled ETF. The time and effort spent might outweight the lower withholding tax rates.

For Interactive Brokers, typically you pay 0.05% for UK listed ETFs (excluding FX fees). For a comparison across some of the more popular brokerages (including SC and Saxo), you might want to refer to this article: https://www.alvinpoh.com/standard-chartered-sta...

Do take note of the monthly activity fee chargeable for Interactive Brokers.