Substantial increases in South American monsoon precipitation during Heinrich Stadials point toward decreased cross-equatorial heat transport as the main driver of monsoonal hydroclimate variability at millennial time-scales. In order to better constrain the exact timing as well as the regional expression of Heinrich Stadials over tropical South America we present a multi-proxy paleo-precipitation reconstruction for Heinrich Stadial 1 (HS1), based on two precisely dated high-temporal resolution speleothem records in combination with marine records of terrestrial organic and inorganic matter input into the western equatorial Atlantic. Covering a wide portion of eastern South America monsoon domain the HS1 typifies a Mega SACZ episodes presenting a double plunge structured characterized by least two important events of increased monsoonal precipitation centered at 15.4 and 17.38 kyr B.P., here labeled as HS1a and HS1c, respectively, desiccant by a long-standing dry excursion ranging from 16.66 to 16.11 kyr BP, labeled as HS1b.