Colonial Cartagena was built to face inward. A merchant house inside the ramparts turns a blank lime-washed wall and one heavy door to the street, then spends everything it has on the patio in the middle: a well, a breadfruit tree, a first-floor balcony running all the way round. Four centuries on, a great many of those houses are hotels, and the logic has not changed. The bedrooms are often small, sometimes have no exterior window at all, and are startlingly unequal to one another inside the same building. The courtyard, the plunge pool cut into its tiles and the roof terrace above are what you are actually paying for, and all three are shared.
That reorders the whole decision. In most cities you choose a hotel and inherit its neighbourhood. In Cartagena the four plausible neighbourhoods sit within roughly twenty minutes of each other on foot, they are genuinely different propositions, and the hotels within any one of them are more alike than their photographs suggest. So choose the quarter first, the building second, and then choose the room with as much care as you gave the other two.
The geography you are choosing between
Centro is the grid inside the walls: Plaza Santo Domingo, Plaza de Bolivar, the cathedral, the jewellers under the vaulted arcades. It is where the cruise passengers and the horse carriages concentrate in the middle of the day, and where the streets empty pleasantly again by around nine in the evening. San Diego, the quarter at the northern end of the same walled grid, is the identical architecture with a fraction of the traffic - smaller plazas, more residents who actually live there, several of the city's better-regarded restaurants. Local guides put the walk across the entire walled city at under twenty minutes, which is worth holding on to whenever a booking site describes something as far from the centre.
La Matuna is the strip of mid-century offices, banks and the Transcaribe rapid-bus spine that separates the old city from Getsemani. It is not somewhere to sleep, but you will cross it constantly, and it takes about five minutes on foot.
Getsemani begins immediately outside the Torre del Reloj gate. Until fairly recently it was the working quarter - dockers, salsa, the old bus station - and it is now where the city's evenings end up, with the murals, the street food and the young crowd to match. Rooms there run cheaper than the equivalent inside the walls.
Bocagrande, with El Laguito at its tip and Castillogrande on its bay side, is the high-rise peninsula south-west of the old city: apartment towers, chain hotels, supermarkets, the city beaches. Reckon on ten to fifteen minutes by taxi to the walls depending on traffic, or a walk of a little over half an hour along the seafront.
Two further options exist and are worth knowing about even if you do not take them. Manga, an island of republican-era mansions over the bridge, is quiet, residential and cheap, and you will taxi everywhere from it. La Boquilla and the Zona Norte strip, fifteen-odd minutes north towards the airport, is where the resorts are; the beaches are better and there is nothing to walk to.