It is Ferrer's 11th career title and extends his career head-to-head record to 6-0 against Almagro.
"I didn't think I could win here twice in a row and I realize I am having the best season start of my career this year," Ferrer said. "I hope I can continue like that this season."
Ferrer converted his first six break points and was denied his seventh only when Almagro hit a clutch forehand that landed on the line to save a match point in the seventh game of the third set.
Almagro could convert on just four of 13 break chances.
"It was a very intense match with a lot of rallies in the first and second set; we played a lot of great points," Ferrer said. "In the third [set], I think I was better physically and he started making more mistakes."
Ferrer has started the season with 14 wins in 16 matches, a record that includes titles in Auckland and Acapulco and a semifinal run at the Australian Open.
Almagro, seeded third, came into the final with a 13-match winning streak after earning titles in Argentina and Brazil in the past two weeks.
He was also bidding to become the first player to win three of the four events on the ATP Tour's Latin American clay-court season.
"I am disappointed right now that I couldn't close this first set -- maybe things would have been different," Almagro said.
"It's been an unbelievable South American swing for me. I played nonstop for three weeks at a very high level and I know I need to be proud and happy about it."
It was Dulko's fourth WTA title. Parra Santonja has now played in two finals and is still looking for her first title.