| BEL | 0 | Russia | RU-BEL |
| Belgrade | 0 | Serbia | RS-00 |
| Beltinci Municipality | 0 | Slovenia | SI-002 |
| BEN | 0 | United Kingdom | GB-BEN |
| Benedikt Municipality | 0 | Slovenia | SI-148 |
| Benešov | 0 | Czech Republic | CZ-201 |
| Benevento Province | 0 | Italy | IT-BN |
| Berane Municipality | 0 | Montenegro | ME-03 |
| Berat County | 0 | Albania | AL-01 |
| Berat District | 0 | Albania | AL-BR |
| Beroun | 0 | Czech Republic | CZ-202 |
| Berovo Municipality | 0 | Republic of North Macedonia | MK-03 |
| Beverīna Municipality | 0 | Latvia | LV-017 |
| BEX | 0 | United Kingdom | GB-BEX |
| BFS | 0 | United Kingdom | GB-BFS |
| BGE | 0 | United Kingdom | GB-BGE |
| BGW | 0 | United Kingdom | GB-BGW |
| BH | 0 | Romania | RO-BH |
| Bijelo Polje Municipality | 0 | Montenegro | ME-04 |
| BIR | 0 | United Kingdom | GB-BIR |
| Birgu | 0 | Malta | MT-03 |
| Birkirkara | 0 | Malta | MT-04 |
| Birštonas Municipality | 0 | Lithuania | LT-05 |
| Biržai District Municipality | 0 | Lithuania | LT-06 |
| Birżebbuġa | 0 | Malta | MT-05 |
| Bistrica ob Sotli Municipality | 0 | Slovenia | SI-149 |
| Bitola Municipality | 0 | Republic of North Macedonia | MK-04 |
| Bjelovar-Bilogora County | 0 | Croatia | HR-07 |
| BK | 0 | Hungary | HU-BK |
| BKM | 0 | United Kingdom | GB-BKM |
| BL | 0 | Switzerland | CH-BL |
| BL | 0 | Slovakia | SK-BL |
| BLA | 0 | United Kingdom | GB-BLA |
| Blagoevgrad Province | 0 | Bulgaria | BG-01 |
| Blansko | 0 | Czech Republic | CZ-641 |
| Bled Municipality | 0 | Slovenia | SI-003 |
| Blekinge | 0 | Sweden | SE-K |
| Bloke Municipality | 0 | Slovenia | SI-150 |
| BLY | 0 | United Kingdom | GB-BLY |
| BMH | 0 | United Kingdom | GB-BMH |
| BN | 0 | Romania | RO-BN |
| BNB | 0 | United Kingdom | GB-BNB |
| BNE | 0 | United Kingdom | GB-BNE |
| BNH | 0 | United Kingdom | GB-BNH |
| BNS | 0 | United Kingdom | GB-BNS |
| Boeotia Regional Unit | 0 | Greece | GR-03 |
| Bogdanci Municipality | 0 | Republic of North Macedonia | MK-05 |
| Bogovinje Municipality | 0 | Republic of North Macedonia | MK-06 |
| Bohinj Municipality | 0 | Slovenia | SI-004 |
| BOL | 0 | United Kingdom | GB-BOL |
| Bor District | 0 | Serbia | RS-14 |
| Borgo Maggiore | 0 | San Marino | SM-06 |
| Borovnica Municipality | 0 | Slovenia | SI-005 |
| Bosilovo Municipality | 0 | Republic of North Macedonia | MK-07 |
| Bosnian Podrinje Canton | 0 | Bosnia and Herzegovina | BA-05 |
| Bourgogne-Franche-Comté | 0 | France | FR-BFC |
| Bovec Municipality | 0 | Slovenia | SI-006 |
| BPL | 0 | United Kingdom | GB-BPL |
| BQ1 | 0 | Netherlands | NL-BQ1 |
| BQ2 | 0 | Netherlands | NL-BQ2 |
| BQ3 | 0 | Netherlands | NL-BQ3 |
| BR | 0 | Moldova | MD-BR |
| BR | 0 | Belarus | BY-BR |
| BR | 0 | Romania | RO-BR |
| Braga | 0 | Portugal | PT-03 |
| Bragança | 0 | Portugal | PT-04 |
| Braničevo District | 0 | Serbia | RS-11 |
| Braslovče Municipality | 0 | Slovenia | SI-151 |
| BRC | 0 | United Kingdom | GB-BRC |
| Brčko District | 0 | Bosnia and Herzegovina | BA-BRC |
| BRD | 0 | United Kingdom | GB-BRD |
| Brda Municipality | 0 | Slovenia | SI-007 |
| Břeclav | 0 | Czech Republic | CZ-644 |
| Brežice Municipality | 0 | Slovenia | SI-009 |
| Brezovica Municipality | 0 | Slovenia | SI-008 |
| Brittany | 0 | France | FR-BRE |
| Brno-město | 0 | Czech Republic | CZ-642 |
| Brno-venkov | 0 | Czech Republic | CZ-643 |
| Brocēni Municipality | 0 | Latvia | LV-018 |
| Brod-Posavina County | 0 | Croatia | HR-12 |
| BRU | 0 | Belgium | BE-BRU |
| Bruntál | 0 | Czech Republic | CZ-801 |
| Brvenica Municipality | 0 | Republic of North Macedonia | MK-08 |
| BRY | 0 | United Kingdom | GB-BRY |
| BRY | 0 | Russia | RU-BRY |
| BS | 0 | Moldova | MD-BS |
| BS | 0 | Switzerland | CH-BS |
| BST | 0 | United Kingdom | GB-BST |
| BT | 0 | Romania | RO-BT |
| BU | 0 | Hungary | HU-BU |
| BU | 0 | Spain | ES-BU |
| BU | 0 | Russia | RU-BU |
| Budva Municipality | 0 | Montenegro | ME-05 |
| Bulqizë District | 0 | Albania | AL-BU |
| BUR | 0 | United Kingdom | GB-BUR |
| Burgas Province | 0 | Bulgaria | BG-02 |
| Burgenland | 0 | Austria | AT-1 |
| Burgundy | 0 | France | FR-D |
| Burtnieki Municipality | 0 | Latvia | LV-019 |
| Buskerud | 0 | Norway | NO-06 |
