Spain's force in Cuba numbered 278,457 soldiers, distributed in 101 Infantry Battalions, 11 Cavalry Regiments, 2 Artillery Regiments, and 4 Marine Battalions. The force in Cuba made up the bulk of Spain's entire military force, being nearly 57 percent of the Army. This force was bolstered by another 82,000 volunteers. Another 10,005 were in Puerto Rico, and 51,331 in the Philippines, for another 12 percent of the Spanish Army.

Although a large force, the Spanish Army of the time was somewhat decrepit, manned with poor quality conscripts (those who could afford to pay the tax to avoid universal conscription always did), and never with enough equipment, even though they did carry decent Mauser rifles. Although commanding a large part of the Spanish budget, the bloated officer corps (1:4 officer:enlisted ratio!) ate up much of that with their salaries. The aloof officer corps wasn't up to the task of leadership, and the men were not all that easy to lead in any case.

At sea, Cuba and Puerto Rico were defended by 8 cruisers, 6 destroyers, and 49 other small craft manned by 2,800 sailors and 600 marines. As with the Army though, the Navy was a paper tiger at best, as barely any of the Spanish fleet was up to modern standards and able to go toe-to-toe with the US Navy, which as it turned out, made mincemeat of 'em.

"Spain, Army" and "Spain, Navy" from Encyclopedia of the Spanish-American and Philippine American Wars, ed. by Spencer C. Tucker