This study examines two distinct types of El Niño–Southern Oscillation (ENSO) in the tropical Pacific: the eastern-Pacific (EP) type and the central-Pacific (CP) type. Using a combination of empirical orthogonal function (EOF) analysis and linear regression, the researchers identify and characterize these two types based on their spatial structures, temporal evolutions, and teleconnections. The EP type is characterized by SST anomalies centered in the eastern equatorial Pacific, extending along the coast of South America, and showing a strong teleconnection with the tropical Indian Ocean. In contrast, the CP type has its SST anomalies confined to the central Pacific, with a weaker teleconnection to the Indian Ocean. The EP type exhibits a basin-wide thermocline and surface wind variation pattern, while the CP type is influenced more by local atmospheric forcing. The EP type shows a phase-reversal signature in its anomaly evolution, indicating a cycle-like behavior, whereas the CP type appears more as an event. The EP type has experienced a stronger interdecadal change, with its periodicity shifting from 2 to 4 years around 1976/77, while the CP type remains relatively stable. The study also highlights the need for new ENSO indices to better monitor these two distinct types of ENSO activity.This study examines two distinct types of El Niño–Southern Oscillation (ENSO) in the tropical Pacific: the eastern-Pacific (EP) type and the central-Pacific (CP) type. Using a combination of empirical orthogonal function (EOF) analysis and linear regression, the researchers identify and characterize these two types based on their spatial structures, temporal evolutions, and teleconnections. The EP type is characterized by SST anomalies centered in the eastern equatorial Pacific, extending along the coast of South America, and showing a strong teleconnection with the tropical Indian Ocean. In contrast, the CP type has its SST anomalies confined to the central Pacific, with a weaker teleconnection to the Indian Ocean. The EP type exhibits a basin-wide thermocline and surface wind variation pattern, while the CP type is influenced more by local atmospheric forcing. The EP type shows a phase-reversal signature in its anomaly evolution, indicating a cycle-like behavior, whereas the CP type appears more as an event. The EP type has experienced a stronger interdecadal change, with its periodicity shifting from 2 to 4 years around 1976/77, while the CP type remains relatively stable. The study also highlights the need for new ENSO indices to better monitor these two distinct types of ENSO activity.