This is a list of postcodes in the CO12 3 area covering the areas of Harwich, Tendring. The area contains approximately 3,304 households with a population of about 7,060 (2011 census)
 Active postcode
Active postcode 
   Postcode no longer in use
Postcode no longer in use| Postcode | Latitude | Longitude | Easting | Northing | Grid reference | Active? | 
|---|---|---|---|---|---|---|
| CO12 3QL | 51.938014 | 1.277357 | 625377 | 231687 | TM253316 | Yes | 
| CO12 3QN | 51.934647 | 1.276529 | 625337 | 231310 | TM253313 | Yes | 
| CO12 3QP | 51.937234 | 1.277271 | 625375 | 231600 | TM253315 | Yes | 
| CO12 3QQ | 51.935028 | 1.276732 | 625349 | 231353 | TM253313 | Yes | 
| CO12 3QR | 51.936303 | 1.279051 | 625502 | 231502 | TM255315 | No | 
| CO12 3QT | 51.934996 | 1.278825 | 625493 | 231356 | TM254313 | Yes | 
| CO12 3QU | 51.937388 | 1.279829 | 625550 | 231625 | TM255316 | Yes | 
| CO12 3QW | 51.935433 | 1.276063 | 625301 | 231396 | TM253313 | Yes | 
| CO12 3RA | 51.935524 | 1.280551 | 625609 | 231420 | TM256314 | Yes | 
| CO12 3RB | 51.934508 | 1.27892 | 625502 | 231302 | TM255313 | No | 
| CO12 3RD | 51.934017 | 1.278477 | 625474 | 231246 | TM254312 | Yes | 
| CO12 3RE | 51.934385 | 1.279144 | 625518 | 231289 | TM255312 | No | 
| CO12 3RF | 51.934713 | 1.279619 | 625549 | 231327 | TM255313 | Yes | 
| CO12 3RG | 51.933602 | 1.27785 | 625433 | 231198 | TM254311 | Yes | 
| CO12 3RH | 51.933236 | 1.27711 | 625384 | 231155 | TM253311 | Yes | 
| CO12 3RJ | 51.932591 | 1.276394 | 625338 | 231081 | TM253310 | Yes | 
| CO12 3RL | 51.934169 | 1.278808 | 625496 | 231264 | TM254312 | Yes | 
| CO12 3RN | 51.932775 | 1.275243 | 625258 | 231098 | TM252310 | Yes | 
| CO12 3RP | 51.931767 | 1.274646 | 625222 | 230984 | TM252309 | Yes | 
| CO12 3RR | 51.931605 | 1.2743 | 625199 | 230965 | TM251309 | Yes | 
| CO12 3RS | 51.932322 | 1.27278 | 625091 | 231040 | TM250310 | Yes | 
| CO12 3RT | 51.932017 | 1.271463 | 625002 | 231002 | TM250310 | No | 
| CO12 3RU | 51.932017 | 1.271463 | 625002 | 231002 | TM250310 | No | 
| CO12 3RW | 51.932538 | 1.274091 | 625180 | 231068 | TM251310 | Yes | 
| CO12 3RX | 51.931079 | 1.272515 | 625079 | 230901 | TM250309 | Yes | 
| CO12 3RY | 51.932228 | 1.271333 | 624992 | 231025 | TM249310 | Yes | 
| CO12 3RZ | 51.930906 | 1.271324 | 624998 | 230878 | TM249308 | Yes | 
| CO12 3SA | 51.933073 | 1.273941 | 625167 | 231127 | TM251311 | Yes | 
| CO12 3SB | 51.933877 | 1.274771 | 625220 | 231219 | TM252312 | Yes | 
| CO12 3SD | 51.926067 | 1.262898 | 624443 | 230314 | TM244303 | Yes | 
| CO12 3SE | 51.933116 | 1.274308 | 625192 | 231133 | TM251311 | Yes | 
| CO12 3SF | 51.925841 | 1.264555 | 624558 | 230294 | TM245302 | Yes | 
| CO12 3SG | 51.934056 | 1.275788 | 625289 | 231242 | TM252312 | Yes | 
| CO12 3SH | 51.933404 | 1.276235 | 625323 | 231171 | TM253311 | Yes | 
| CO12 3SJ | 51.934225 | 1.277139 | 625381 | 231265 | TM253312 | Yes | 
| CO12 3SL | 51.926613 | 1.263636 | 624491 | 230377 | TM244303 | Yes | 
| CO12 3SN | 51.925474 | 1.262884 | 624445 | 230248 | TM244302 | Yes | 
| CO12 3SP | 51.931429 | 1.268351 | 624791 | 230927 | TM247309 | Yes | 
| CO12 3SQ | 51.933233 | 1.275291 | 625259 | 231149 | TM252311 | Yes | 
| CO12 3SR | 51.93193 | 1.276229 | 625330 | 231007 | TM253310 | Yes | 
| CO12 3SS | 51.930682 | 1.274523 | 625219 | 230863 | TM252308 | Yes | 
| CO12 3ST | 51.929416 | 1.273471 | 625153 | 230719 | TM251307 | Yes | 
| CO12 3SU | 51.93009 | 1.269592 | 624883 | 230782 | TM248307 | Yes | 
| CO12 3SW | 51.925597 | 1.262326 | 624406 | 230260 | TM244302 | Yes | 
| CO12 3SX | 51.926125 | 1.261448 | 624343 | 230316 | TM243303 | Yes | 
| CO12 3SY | 51.937695 | 1.279793 | 625546 | 231659 | TM255316 | No | 
| CO12 3SZ | 51.929038 | 1.268933 | 624843 | 230663 | TM248306 | Yes | 
| CO12 3TA | 51.927387 | 1.266849 | 624708 | 230473 | TM247304 | Yes | 
| CO12 3TB | 51.928196 | 1.2633 | 624460 | 230552 | TM244305 | Yes | 
| CO12 3TD | 51.928151 | 1.263951 | 624505 | 230549 | TM245305 | Yes | 
| CO12 3TE | 51.93014 | 1.262626 | 624404 | 230766 | TM244307 | Yes | 
| CO12 3TF | 51.937695 | 1.279793 | 625546 | 231659 | TM255316 | No | 
| CO12 3TG | 51.929623 | 1.261818 | 624351 | 230706 | TM243307 | Yes | 
| CO12 3TH | 51.930269 | 1.263494 | 624463 | 230783 | TM244307 | Yes | 
| CO12 3TJ | 51.929252 | 1.263842 | 624492 | 230671 | TM244306 | Yes | 
| CO12 3TL | 51.929565 | 1.265858 | 624629 | 230712 | TM246307 | Yes | 
| CO12 3TN | 51.928782 | 1.267489 | 624745 | 230630 | TM247306 | Yes | 
| CO12 3TP | 51.928785 | 1.266063 | 624647 | 230626 | TM246306 | Yes | 
| CO12 3TQ | 51.92824 | 1.246441 | 623301 | 230505 | TM233305 | Yes | 
| CO12 3TR | 51.927386 | 1.263008 | 624444 | 230461 | TM244304 | Yes | 
| CO12 3TS | 51.926105 | 1.258609 | 624148 | 230305 | TM241303 | Yes | 
| CO12 3TT | 51.924594 | 1.260565 | 624290 | 230143 | TM242301 | Yes | 
| CO12 3TU | 51.925078 | 1.26223 | 624402 | 230202 | TM244302 | No | 
| CO12 3TW | 51.928281 | 1.26543 | 624606 | 230568 | TM246305 | Yes | 
| CO12 3TX | 51.925981 | 1.247137 | 623360 | 230256 | TM233302 | Yes | 
| CO12 3TY | 51.929324 | 1.271267 | 625002 | 230702 | TM250307 | No | 
| CO12 3TZ | 51.922492 | 1.259802 | 624248 | 229907 | TM242299 | Yes | 
| CO12 3UA | 51.925995 | 1.256085 | 623975 | 230285 | TM239302 | Yes | 
| CO12 3UB | 51.925954 | 1.255296 | 623921 | 230278 | TM239302 | Yes | 
| CO12 3UD | 51.926011 | 1.253889 | 623824 | 230280 | TM238302 | Yes | 
| CO12 3UE | 51.925659 | 1.254576 | 623873 | 230243 | TM238302 | Yes | 
| CO12 3UF | 51.925294 | 1.253473 | 623799 | 230199 | TM237301 | Yes | 
| CO12 3UH | 51.928054 | 1.244391 | 623161 | 230478 | TM231304 | Yes | 
| CO12 3UJ | 51.925586 | 1.251676 | 623674 | 230226 | TM236302 | Yes | 
| CO12 3UL | 51.925022 | 1.250922 | 623625 | 230161 | TM236301 | Yes | 
| CO12 3WA | 51.925022 | 1.250922 | 623625 | 230161 | TM236301 | No | 
| CO12 3WB | 51.937695 | 1.279793 | 625546 | 231659 | TM255316 | No | 
| CO12 3WD | 51.925022 | 1.250922 | 623625 | 230161 | TM236301 | No | 
| CO12 3WE | 51.937695 | 1.279793 | 625546 | 231659 | TM255316 | No | 
| CO12 3WF | 51.937695 | 1.279793 | 625546 | 231659 | TM255316 | No | 
| CO12 3WG | 51.925022 | 1.250922 | 623625 | 230161 | TM236301 | No | 
| CO12 3WH | 51.937695 | 1.279793 | 625546 | 231659 | TM255316 | No | 
| CO12 3WJ | 51.937695 | 1.279793 | 625546 | 231659 | TM255316 | No | 
| CO12 3WL | 51.937695 | 1.279793 | 625546 | 231659 | TM255316 | No | 
| CO12 3WN | 51.937695 | 1.279793 | 625546 | 231659 | TM255316 | No | 
| CO12 3WP | 51.937695 | 1.279793 | 625546 | 231659 | TM255316 | No | 
| CO12 3WQ | 51.937695 | 1.279793 | 625546 | 231659 | TM255316 | No | 
| CO12 3WR | 51.937695 | 1.279793 | 625546 | 231659 | TM255316 | No | 
| CO12 3WS | 51.937695 | 1.279793 | 625546 | 231659 | TM255316 | No | 
| CO12 3WT | 51.937695 | 1.279793 | 625546 | 231659 | TM255316 | No | 
| CO12 3WU | 51.937695 | 1.279793 | 625546 | 231659 | TM255316 | No | 
| CO12 3WW | 51.937695 | 1.279793 | 625546 | 231659 | TM255316 | No | 
| CO12 3WX | 51.937695 | 1.279793 | 625546 | 231659 | TM255316 | No | 
| CO12 3WY | 51.937695 | 1.279793 | 625546 | 231659 | TM255316 | No | 
| CO12 3WZ | 51.937695 | 1.279793 | 625546 | 231659 | TM255316 | No | 
| CO12 3XA | 51.937695 | 1.279793 | 625546 | 231659 | TM255316 | No | 
| CO12 3XQ | 51.937695 | 1.279793 | 625546 | 231659 | TM255316 | No | 
| CO12 3YY | 51.936877 | 1.279748 | 625547 | 231568 | TM255315 | No |