Captain Brathwaite recorded his 12th Test ton as he made 116 while Chanderpaul, son of West Indies great Shivnarine, closed on 101.
It is the highest opening partnership by West Indians since Chris Gayle and Kieran Powell scored 254 against New Zealand in Antigua 11 years ago.
Saturday’s play had been abandoned because of rain soon after lunch with the tourists 112-0 and the inclement weather intervened again.
Play was only able to start at 1500 local time (1300 GMT) on Sunday after sawdust had been scattered across the damp areas in the outfield.
As was the case on the opening day, the West Indies openers took few chances, scoring at fewer than two and half runs per over against some tight Zimbabwe bowling on a sluggish pitch.
Brathwaite, who has been in a rich run of form, looked the more comfortable and was the first to reach his century.
By the close he had faced 246 balls and hit seven fours.
Chanderpaul was more circumspect although there were moments when he played like his father who only retired from Test cricket eight years ago, having racked up 30 centuries in 164 Tests.
While it took his father 19 Tests to reach his first century, Chanderpaul junior has needed just three.
The 26-year-old left-hander only made his debut in Perth against Australia in November when he scored 51 and 45. He followed that with 47 and 17 in Adelaide and looked at home alongside Brathwaite in Bulawayo.
He struck 10 fours and a six during the course of his innings, bringing up his century with a neat tuck behind square for a single.
“He (Chanderpaul) looks to be world-class and is a top opener,” said Brathwaite at the close. “Glad we have got some big partnerships thus far and would love to continue.”
Each of the Zimbabwe bowlers deserves credit for keeping a tight rein on the West Indies scoring, spinner Wellington Masakadza conceding just 30 runs from a tight 16 overs which included six maidens.
The match, which is the first for the West Indies with Brian Lara acting as performance mentor, is the first of two in a Test series in Bulawayo. The second is scheduled to start on February 12.