Mr Colao said Mr Read and Ms Della Valle were were the best people to take the group into its next stage, adding that the management team he has created would be his "real legacy".
Separately, Vodafone said that, effective October 2018, CEO Colao will be succeeded by Chief Financial Officer Nick Read.
Calao has been in the role for almost a decade, creating one of the world's leading communications companies with the largest mobile network in Europe, all while being a pioneer in the development of IoT.
Read attained his present post in 2014 following a successful spell at the group's emerging markets division spanning Africa, the Middle East and Asia Pacific.
Colao will be replaced by Vodafone's finance director since 2014, Nick Read whose wealth of global experience made him a likely candidate for the position.
On behalf of the board, I would like to express our gratitude to Vittorio for an outstanding tenure. I am confident Vodafone will benefit greatly from his experience, insight and wisdom in his new role as group chief executive.More news: Reus, Neuer on Loew's list for World Cup
More news: CBS Sues Controlling Shareholder National Amusements, Accuses Shari Redstone Of Undermining Board
More news: Cannes 2018: Mahira Khan dazzles on the red carpet
The 56-year-old Italian said that the time was right to move on with most of the "reshaping" of Vodafone now complete following the recent spate of deals.
This has led to a mixed full year to 31 March 2018 operating performance, although one that looks pretty decent overall.
Vodafone further updated investors on its tie-up in India where the group's local unit is merging with Idea Cellular, noting that the deal is expected to close next month.
Vodafone on May 9 agreed to buy cable group Liberty Global's German, Czech, Hungarian and Romanian businesses for 18.4 billion euros ($21.8 billion), including debt.
Meanwhile, group profit swelled to €2.8bn, reversing last year's loss of €6.1bn.
"Our sustained investment in network quality supported robust commercial momentum: we added a record number of fixed [Next Generation Networks] and converged customers in Q4, mobile data usage continues to grow strongly and we grew both revenues and margins in Enterprise, despite roaming headwinds, and continued to reduce operating costs".
Excluding the negative impact of net roaming declines in Europe, the benefits of settlements in the United Kingdom and Germany and the introduction of handset financing in the United Kingdom, organic adjusted EBITDA grew by 7.9%.