The 21-year-old will link up with the U's until January 2, 2016 and could make his debut against Scunthorpe United tomorrow.
He leaves Charlton for the first time to gain first-team experience in League One having made just one substitute appearance in the Championship this term.
Harriott is Colchester's second signing in two days after they snapped up Owen Garvan yesterday.
Restore Data
| Team | P | W | D | L | F | A | GD | PTS | |
| C | Portsmouth | 46 | 28 | 13 | 5 | 78 | 41 | 37 | 97 |
| P | Derby CountyDerby | 46 | 28 | 8 | 10 | 78 | 37 | 41 | 92 |
| 3 | Bolton WanderersBolton | 46 | 25 | 12 | 9 | 86 | 51 | 35 | 87 |
| 4 | Peterborough UnitedPeterborough | 46 | 25 | 9 | 12 | 89 | 61 | 28 | 84 |
| 5 | Oxford UnitedOxford Utd | 46 | 22 | 11 | 13 | 79 | 56 | 23 | 77 |
| 6 | Barnsley | 46 | 21 | 13 | 12 | 82 | 64 | 18 | 76 |
| 7 | Lincoln CityLincoln | 46 | 20 | 14 | 12 | 65 | 40 | 25 | 74 |
| 8 | Blackpool | 46 | 21 | 10 | 15 | 65 | 48 | 17 | 73 |
| 9 | Stevenage | 46 | 19 | 14 | 13 | 57 | 46 | 11 | 71 |
| 10 | Wycombe WanderersWycombe | 46 | 17 | 14 | 15 | 60 | 55 | 5 | 65 |
| 11 | Leyton Orient | 46 | 18 | 11 | 17 | 53 | 55 | -2 | 65 |
| 12 | Wigan AthleticWigan | 46 | 20 | 10 | 16 | 63 | 56 | 7 | 62 |
| 13 | Exeter CityExeter | 46 | 17 | 10 | 19 | 46 | 61 | -15 | 61 |
| 14 | Northampton TownNorthampton | 46 | 17 | 9 | 20 | 57 | 66 | -9 | 60 |
| 15 | Bristol Rovers | 46 | 16 | 9 | 21 | 52 | 68 | -16 | 57 |
| 16 | Charlton AthleticCharlton | 46 | 11 | 20 | 15 | 64 | 65 | -1 | 53 |
| 17 | Reading | 46 | 16 | 11 | 19 | 68 | 70 | -2 | 53 |
| 18 | Cambridge UnitedCambridge | 46 | 12 | 12 | 22 | 39 | 61 | -22 | 48 |
| 19 | Shrewsbury TownShrewsbury | 46 | 13 | 9 | 24 | 35 | 67 | -32 | 48 |
| 20 | Burton Albion | 46 | 12 | 10 | 24 | 39 | 67 | -28 | 46 |
| R | Cheltenham TownCheltenham | 46 | 12 | 8 | 26 | 41 | 65 | -24 | 44 |
| R | Fleetwood TownFleetwood | 46 | 10 | 13 | 23 | 49 | 72 | -23 | 43 |
| R | Port Vale | 46 | 10 | 11 | 25 | 41 | 74 | -33 | 41 |
| R | Carlisle UnitedCarlisle | 46 | 7 | 9 | 30 | 41 | 81 | -40 | 30 |
| > League One Full Table | |||||||||
