Throughout 1818 and 1819 Barradas fought with the Third Division of Brigadier Jose Marie Barreiro and he won further fame for his stirring speech and heroic charge at the battle of Pantano de Vargas on July 25, 1819 against Simon Bolivar. In that incident he dislodged some 500 rebel troops with only 80 grenadiers. He was commended by his general for this but not long after the royal army was all but wiped out in the disastrous August 7 battle of Boyaca, which Barradas only narrowly survived. Afterwards, Barradas moved to Cartagena de Indias, joining the garrison there and was given command of a grenadier company from Leon. In the ensuing battle of September 1, 1820 he was badly wounded but again cited for great heroism in the face of a numerically superior foe, earning the Cross of San Fernando for his bravery. Subsequently transferred to Cuba he was given command of a line battalion of infantry when King Fernando VII, after moving to Seville, received Barradas after being restored by the campaign of the “Sons of St Louis”. It was Barradas who was entrusted with the royal decree proclaiming the restoration of the absolute monarchy to be sent to the commanders in Cuba.
Only the year before, the Mexican government has passed the “Law of Expulsion” which ordered the deportation of all foreigners in Mexico and the Spanish were particularly singled out. This greatly offended Spain and finally there was some international sympathy for taking action, particularly when the British Duke of Wellington said his country would not object to Spain attempting to regain Mexico. In the summer of 1829 Brigadier Isidro Barradas arrived in Havana and began gathering an expeditionary force of between three and four thousand men which he embarked for Mexico on July 5 in a fleet of one ship of the line, two frigates, two gunboats and fifteen transports. Many of the men assembled were Spaniards who had been expelled from Mexico and they had convinced Barradas that with just a little show of force the Mexican public would rise up to restore the authority of the King of Spain.
Unfortunately, things seemed to go badly from the start. A heavy storm in the Bay of Campeche dispersed the Spanish fleet and it took weeks for the ships to reassemble off Veracruz and one transport with 400 troops had to divert to New Orleans for repairs. When they finally moved off Cabo Rojo near Tampico the heavy seas made it almost impossible to land the troops. After scouting the area the Spanish finally put ashore and had a minor clash with a Mexican patrol on July 31 near Pueblo Viejo. Meanwhile, at Tampico, a Mexican army was assembling under General Antonio Lopez de Santa Anna. Although he lacked the numbers to launch an immediate assault, Santa Anna besieged the Spanish army at Pueblo Viejo. Despite what Barradas had been told the Mexicans did not rise up in support of Spain and the army of Santa Anna only grew stronger while the Spanish forces were weakened by fever, endemic in the coastal lowlands and exacerbated by the dwindling supply of food and clean water. Barradas held on, hoping for rescue or some political shift in Mexico but it was to no avail. Finally, on September 11, 1829 General Isidro Barradas had no choice but to surrender to the combined forces of General Santa Anna and General Manuel Mier y Teran.
General Barradas remained in France for the rest of his life, having a son there and living in quite poor conditions. Yet, as King Fernando VII was on his deathbed, Barradas wrote him a last letter, asserting his innocence of the charges against him and pledging his loyalty to the King and his daughter Princess Isabella. After the King died the Carlist faction tried to enlist the support of General Barradas but, though he was somewhat sympathetic, refused to break his oath of loyalty to the new Queen Isabella II. He died in Marseille on August 14, 1835 after a lifetime of service to his King and country only to end it the victim of lies and injustice.