Australia, Austria, Belgium, Brazil, Canada, France, Germany, Italy, Luxembourg, Netherlands, Poland, Portugal, Singapore, Spain, Sweden, Turkey, the US, and the UK will all take part in Prime Big Deal Days in 2024 via their respective storefronts. Japan will have its own Big Deal Days later in October. China is notably missing from this year's list of participating countries.
If your country doesn't have its own localized version of Amazon, you may still be able to make purchases from a neighboring variant, but usual restrictions likely apply, so check your local Amazon international shipping terms and conditions.