Following the implementation of e-Commerce VAT changes in Northern Ireland from July 1, 2021, online marketplaces are responsible for collecting and accounting for the VAT on goods sold by non-EU businesses located in Northern Ireland (NI), at the point of sale, and sold to NI customers. NI established businesses can also opt to join the OSS Union scheme.
Joining the OSS scheme
Companies who want to apply to the scheme must:
Furthermore, digital services provided to customers in the EU must not be included in the OSS VAT Return. Only B2C distance sales from NI to EU are included in the return. For Online Marketplace (OMPs), supply of goods to customers in the NI should be reported on behalf of a seller outside the UK and EU. Any currency amounts must be entered in pounds sterling and the VAT rates of the EU country where your customer is located is used.
Corrective Returns
After submitting an OSS return, you will have the option to make corrections to an earlier OSS return by changing the total VAT amounts you have previously declared to each country and by adding VAT amounts on sales for each country that was not included on an earlier return. When correcting previous returns, errors can only be corrected:
Over-declaration of VAT
The EU country where you have over-declared is responsible for any refunds.
Source: Completing a One Stop Shop VAT Return; Submit your One Stop Shop VAT Return