Having been promoted to the staff next year, he made two campaigns under the Duke of York in Flanders, after which he proceeded to the West Indies as surgeon, 23rd royal Welsh Fusiliers.
In 1799 he accompanied the expedition to the Helder, and after its failure was sent by the Duke of York to the headquarters of the French general, Guillaume Brune, with a flag of truce, to arrange for the exchange of the wounded.
He was also attached to the Russian troops, which had co-operated with the British in North Holland, and had been ordered to winter in the Channel Islands until the breaking up of the ice in the Baltic should allow of their return home.
Borland was chief medical officer of the army in the southern counties, under command of Sir David Dundas, at the time of the threatened French invasion.
From 1810 to 1810 Borland was principal medical officer in the Mediterranean, during which period he organised the hospitals of the Anglo-Sicilian contingent, the efficiency and unprecedented economy of which formed the subject of a special official minute on the breaking up of the force.
He also accompanied the force sent to assist the Austrians in expelling Joachim Murat from Naples, and the troops under Major-general Sir Robert Henry MacFarlane, despatched from Genoa, which held Marseilles and blockaded Toulon at the time of the Waterloo campaign.