This is a three-aisled cruciform basilica in late Brabantine Gothic style. Its construction started in 1462 and was completed in 1564. The church replaced an older one of part of the tower was saved. The lower part of this tower dates from ca. the year 1200.
Several architects worked on the church. In 1462, under the leadership of Everaert Spoorwater, work started on the choir and ambulatory. Herman de Waghemakere lead the construction of the nave starting in 1481. Willem van Sassen completed the facade in ca. 1453. Laurens II Keldermans was in charge of the project after 1512.
The church was built of brick and covered on the outside with limestone. Choir and nave are seperated from each other by the tower. The original spire was destroyed by lightning in 1668. In 1724 a new spire in Classical style was added. The octagonal tower at the crossing is unique for a church in Brabantine Gothic style but much more common for a Flemish church. Of course Hulst was still part of the Duchy of Flanders at that time. Unlike the nave, the choir has flying buttresses to support the vaults. These flying buttresses are connected to the buttresses by peculiar walls. Traces indicate that the nave was intended to have stone vaults too, but instead in the 17th century a flat wooden ceiling was installed.
Although the St. Willibrordus is not really a big church it's obvious that Hulst must have been a flourishing place when the church was built. But in 1645 troops of the Republic conquered the town, starting a long period of decay. The catholic faith was outlawed and the church confiscated for use by the protestants. In 1806 king Lodewijk Napoleon gave the choir back to the catholics while the protestants continued to use the transept and nave. A wall seperated the two parts from each other. In 1876 lightning once again struck the tower, causing damage to the rest of the church as well, especially the choir. P.J.H. Cuypers designed a new neo-Gothic spire to replace the damaged one in Classical style. Cuypers, out of his own will, also made a plan for the restoration of the entire church which was not executed. Architect P. Soffers started the reparations to the transept and choir, a job that was completed by P.J. van Genk in the 1890's. In 1929 the protestants sold their part of the church to the catholics. The dividing wall was removed and in 1931 a restoration started, executed by Jos Cuypers and his son Pierre jr.. P.J.H. Cuypers' plan was not used, instead a new plan was made. One of the major changes was the construction of stone vaults in the nave. The restoration was completed in 1933. In 1935 the pope granted the church the title of Basilica Minor.
In 1944 the church was damaged by artillery fire. P.J.H. Cuypers' spire was lost and in 1957 replaced by a new one, designed by J. Brouwer and made of concrete.