| Port Code | Port Name | Country |
| GBNTW | Nantwich | United Kingdom |
| GBNTY | Bentley | United Kingdom |
| GBNUR | Nursling | United Kingdom |
| GBNUT | Newark upon Trent | United Kingdom |
| GBNWB | Newbridge | United Kingdom |
| GBNWC | Newick | United Kingdom |
| GBNWD | Northwood | United Kingdom |
| GBNWK | Newark | United Kingdom |
| GBNWL | North Weald Bassett/London | United Kingdom |
| GBNWO | Newton | United Kingdom |
| GBNWP | Newport Pagnell | United Kingdom |
| GBNWR | Newbridge | United Kingdom |
| GBNWT | Newtown | United Kingdom |
| GBNWY | New York | United Kingdom |
| GBNYL | Newlyn | United Kingdom |
| GBOAK | Oakhamness | United Kingdom |
| GBOAR | Oare | United Kingdom |
| GBOBA | Oban | United Kingdom |
| GBOBM | Ogbourne Maizey | United Kingdom |
| GBOBY | Oldbury | United Kingdom |
| GBODH | Oldham | United Kingdom |
| GBODM | Odiham | United Kingdom |
| GBOET | Coleorton | United Kingdom |
| GBOGP | Osgathorpe | United Kingdom |
| GBOGR | Ongar | United Kingdom |
| GBOHA | Ockham | United Kingdom |
| GBOKE | Stokeham | United Kingdom |
| GBOKH | Okehampton | United Kingdom |
| GBOKK | Old Kilpatrick | United Kingdom |
| GBOKM | Oakham | United Kingdom |
| GBOKW | Oakworth | United Kingdom |
| GBOLD | Old | United Kingdom |
| GBOLN | Olney | United Kingdom |
| GBOLW | Old Woking | United Kingdom |
| GBOLY | Holywood | United Kingdom |
| GBOMA | Omagh | United Kingdom |
| GBOMK | Ormskirk | United Kingdom |
| GBONH | Ongar Hill | United Kingdom |
| GBOPG | Orpington | United Kingdom |
| GBORO | Orton | United Kingdom |
| GBORP | Orchard Portman | United Kingdom |
| GBORT | Orsett | United Kingdom |
| GBOSM | Ottery St. Mary | United Kingdom |
| GBOSN | Ossington | United Kingdom |
| GBOSS | Ossett | United Kingdom |
| GBOSY | Mossley | United Kingdom |
| GBOTH | Otham | United Kingdom |
| GBOTL | Otley | United Kingdom |
| GBOTN | Offerton | United Kingdom |
| GBOTT | Ottershaw | United Kingdom |
| GBOUK | Outer Skerries | United Kingdom |
| GBOUT | Tomintoul | United Kingdom |
| GBOVE | Overton | United Kingdom |
| GBOVR | Over | United Kingdom |
| GBOWR | Oswestry | United Kingdom |
| GBOXD | Oxted | United Kingdom |
| GBOXF | Oxford | United Kingdom |
| GBOXI | Oxhill | United Kingdom |
| GBOXT | Oxshott | United Kingdom |
| GBPAB | Pangbourne | United Kingdom |
| GBPAD | Padstow | United Kingdom |
| GBPAK | Port Askaig | United Kingdom |
| GBPAL | Palnackie | United Kingdom |
| GBPAR | Par | United Kingdom |
| GBPAS | Paisley | United Kingdom |
| GBPBK | Pinchbeck | United Kingdom |
| GBPBL | Parbold | United Kingdom |
| GBPBR | Perry Barr | United Kingdom |
| GBPCD | Pencader | United Kingdom |
| GBPCI | Pencaitland | United Kingdom |
| GBPCK | Peckham | United Kingdom |
| GBPCL | Pickhill | United Kingdom |
| GBPCR | Puckeridge | United Kingdom |
| GBPCT | Prescot | United Kingdom |
| GBPCU | Penicuik | United Kingdom |
| GBPCW | Porthcawl | United Kingdom |
| GBPDG | Podington | United Kingdom |
| GBPDH | Padiham | United Kingdom |
| GBPDI | Port Dinorwic | United Kingdom |
| GBPDW | Paddock Wood | United Kingdom |
| GBPDY | Pudsey | United Kingdom |
| GBPED | Pembroke Dock | United Kingdom |
| GBPEE | Peebles | United Kingdom |
| GBPEL | Peel | United Kingdom |
| GBPEM | Pembroke | United Kingdom |
| GBPEN | Penzance | United Kingdom |
| GBPER | Perth | United Kingdom |
| GBPET | Peterborough | United Kingdom |
| GBPEX | Pettistree | United Kingdom |
| GBPFF | Ponders End | United Kingdom |
| GBPFT | Purfleet | United Kingdom |
| GBPGN | Paignton | United Kingdom |
| GBPGR | Pamber Green | United Kingdom |
| GBPGT | Polegate | United Kingdom |
| GBPGW | Pentre-bâch | United Kingdom |
| GBPHD | Peterhead | United Kingdom |
| GBPHG | Potter Heigham | United Kingdom |
| GBPIK | Prestwick | United Kingdom |
| GBPIN | Pinner | United Kingdom |
| GBPIT | Prittlewell | United Kingdom |