On the previous day, the town of Tholen had successfully repelled the first, relatively modest German assault against the Dutch forces defending the island. These troops had established their positions along the Eendracht, the broad tidal waterway that separated Tholen from the mainland of Noord-Brabant. During the night, however, the exposed forward positions on the eastern bank of the Eendracht were withdrawn, and the defenders consolidated their forces on the western shore.
The defence of the island still held significance for the Allied cause. A German occupation of Tholen could potentially threaten Allied positions on Zuid-Beveland, although developments elsewhere would soon diminish the island's strategic importance. Despite this, no reinforcements were dispatched. The Dutch garrison, still numbering approximately 450 men and lightly equipped with heavy weapons, was left to fend for itself.
At approximately 1000 hours, a German negotiator once again approached the Dutch roadblock, much as had occurred the previous day. This time, however, the Germans had compelled a captured Dutch official to act as their intermediary. Despite the fact that the envoy was a fellow Dutchman, the sergeant sent forward to meet him refused to hear his message. The official was promptly turned away and informed in no uncertain terms that negotiations were out of the question.
It apparently took the Germans several more hours to bring their artillery into position. Only around noon did a German battery open fire on the town of Tholen. During this bombardment, the Dutch battalion commander contacted Rear Admiral Van der Stad, the Territorial Commander in Middelburg, and requested further instructions. Van der Stad praised the battalion for the steadfast resistance it had shown the previous day. He then informed the commander that the garrison was authorised to evacuate the island and redeploy to Schouwen-Duiveland, where its troops could reinforce the local defences.
The decision reflected the rapidly changing strategic situation. With the fall of the Zanddijk Line on the previous day, the continued defence of Tholen had largely lost its military value. What had only recently been considered a key outpost had suddenly become an isolated position with little prospect of influencing the wider course of events.
At approximately 1300 hours, the Dutch units defending the Eendracht began withdrawing towards the western coast of Tholen. A substantial portion of the garrison - around 250 men - successfully evacuated to Schouwen-Duiveland. However, the troops guarding the northern shoreline, including the detachment equipped with the island's only two artillery pieces, as well as several smaller units, were less fortunate. While attempting to secure passage from the small harbour of Stavenisse, they were overtaken and captured by German forces.
The Germans only discovered the Dutch withdrawal after finding the trenches along the Eendracht abandoned. At around 1600 hours, they crossed the waterway and immediately organised a pursuit. Their advance moved swiftly across the island toward its western extremity, where they sought to secure the coastline and guard against any possible French landing attempts. During this rapid advance, German reconnaissance and advance parties intercepted a number of Dutch soldiers who had not yet managed to find transport to Schouwen-Duiveland. These isolated groups were quickly rounded up and taken prisoner.
Thus, yet another potentially useful defensive position was abandoned without a prolonged fight. Although the strategic importance of Tholen had diminished following the collapse of the defences on Zuid-Beveland, the evacuation nonetheless enabled the Germans to secure the island with relative ease and to free forces for operations elsewhere in Zeeland and Noord-Brabant.
Tholen itself suffered relatively little from the scattered artillery fire delivered by the few German 105 mm howitzers brought into action against the town. One remarkable aspect of the bombardment was the large number of shells that failed to detonate. The reason for this remains unclear. It may have been the result of defective ammunition stocks - German forces still possessed substantial quantities of older shells originally intended for the First World War-era FH 16 howitzer, some of which were also used in the newer FH 18 guns. Alternatively, the soft and waterlogged soil around Tholen may have absorbed the impact of the shells in such a way that their percussion fuzes failed to activate. Whatever the cause, the unexploded shells continued to pose a significant hazard. Apart from several houses that were destroyed or heavily damaged, most of the visible damage consisted of shattered windows. Streets were littered with broken glass, but otherwise the bombardment caused relatively limited destruction. Remarkably, no civilian casualties were reported.
Once again, the Germans demonstrated a high degree of preparedness in overcoming the geographical obstacles that characterised the Dutch landscape. Within two hours of crossing the Eendracht, German engineers had delivered floating material and ferried artillery units across the narrow waterway. Guns from Artillerie-Regiment 677 were quickly transported to the most western side of the island and deployed near Stavenisse, where they could support future operations and counter any Allied landing attempts or naval activity in the surrounding waters.
By approximately 1800 hours, Tholen had effectively become German territory.
To the north of the island lay the small peninsula of St. Philipsland, where German patrols had already appeared on 15 May. It was here that the brief engagement between the Dutch minelayer Hr.Ms. Hydra and German anti-tank guns had taken place, resulting in the loss of the Dutch vessel.
On 16 May, the Germans deployed a sizeable force west of the village of Anna Jacobapolder, close to the shores of the Zijpe. Their concentration of troops suggests that they anticipated a possible Allied counterattack or landing operation. In reality, however, the French had little capacity for such initiatives. By this stage of the campaign, the Allied forces in Zeeland were fully occupied with preserving what remained of their own positions and attempting to avoid encirclement. Any thought of mounting a serious counteroffensive had long since given way to the more immediate challenge of survival.