The initial work included: digging the ditch, positioning the earth for the ramparts, and the excavation of stone from nearby quarries to reinforce the ramparts. Progress was slow and in September 1614 Springham asked Peter Benson, a master builder from London, whether he would tender for the building of the Walls. Benson accepted and in return was granted 1,000 acres of land in Donegal along with his fee which, as it turned out, he had great difficulty in collecting.
Sir Edward Doddington of Dungiven was responsible for designing the Walls and also for supervising their construction. However, he neglected his duties to some extent and Captain John Baker was later appointed as his replacement.
Thomas Raven, who worked for the City of London in Ireland, carried out all the surveying and measuring work. Of the actual workers, the labourers were nearly all local inhabitants, while the craftsmen such as slaters, masons, carpenters and plasterers came from London. Over 200 men divided their time between building the Walls and building houses for the settlers.
Mostly local materials were used in the construction. Stones and slate were cut from quarries in the present-day Fahan Street and Quarry Street areas. Rubble left over from previous settlements, including ruined church buildings, was also used. Some poor grade lime was obtained from cockleshells found on a small island near Culmore. Larger quantities of better quality lime were brought in from London to improve the strength of the Walls.
By October 1615 all the money originally allocated for the Plantation had been spent with little to show for it. A further £5,000 had to be raised from the London Companies.
The discovery and quelling of an indented Irsh uprising in July 1615 actually helped speed up the work as the Planters feared further attacks on their unguarded city. This was revealed in a report to the Common Council by Springham and Alderman Peter Proby in October 1616. For the first time a favourable report was made on progress. It began:

Overall, the report stated that good progress had been made, with the Walls half-built in strong fashion, a deep ditch formed and two drawbridges erected. It also mentioned that there were some 214 houses in Derry at that time. Springham and Proby also found that Captain Baker was overseeing the work well and no complaints were received from any quarter.
Captain Nicholas Pynnar, Inspector of Fortifications in Ireland, reported in May 1619 that the Walls had been completed by March that year:

The cost of building Derry's Walls and other defences were later listed as: