Bancontact comes first
Most online payments in Belgium go through Bancontact. A shop that only offers international cards loses customers at the basket.
Payconiq and cards
Payconiq is common for mobile payments; Visa, Mastercard and iDEAL (for shoppers from the Netherlands) complete the list. Mollie, Stripe or Adyen give you all of them in one integration.
Delivery and returns
Shoppers expect bpost, PostNL and DHL. EU rules give a 14-day right of withdrawal, so show it and the return steps before checkout.
Invoices
Show prices incl. BTW, add a BTW number field for business buyers and make invoices Peppol-ready.