Spain has introduced mandatory B2B e‑invoicing under Royal Decree 238/2026, effective from 31 March 2026 but operationally deferred until the public e‑invoicing platform regulation takes effect. The decree sets phased implementation: large businesses with turnover over €8 million must comply within 12 months, while all other businesses follow within 24 months. It also imposes strict invoice status reporting within four calendar days and allows four electronic formats.

Slovakia will enforce mandatory B2B e-invoicing via the Peppol network from 1 January 2027 under Law 385/2025 Z.z., following a voluntary testing period in 2026. All e-invoices must use the EN 16931 XML standard (UBL 2.1 or CII), be issued within 15 days, and reported within 5 days, with penalties up to €10,000 per infraction and €100,000 for repeated violations.

Romania’s new e-VAT pre-filled return system requires taxpayers to approve a monthly list of VAT transactions derived from e-invoicing and SAF‑T and reconcile it with their regular VAT return. The penalty‑free soft launch ran from August 2024 to 1 January 2025, giving 20 days to explain discrepancies, and new measures under GEO No. 13/2026 will suspend ANAF’s risk‑classification communication until 31 December 2026.

Spain's Royal Decree 238/2026 introduces mandatory B2B e‑invoicing, with implementation timelines of 12 months for firms over €8 million and 24 months for others, pending a ministerial order on technical specifications. The decree expands the scope to non‑resident suppliers, raising compatibility concerns with the EU VAT Directive. The new system will overlay Spain's existing real‑time reporting and VeriFactu regimes, potentially conflicting with the forthcoming EU ViDA Directive.