EXHIBIT 15.1 INDEPENDENT ACCOUNTANTS' ACKNOWLEDGEMENT LETTER November 11, 2003 To the Board of Directors and Shareholders of Cal Dive International, Inc.: We are aware of the incorporation by reference in the Registration Statements (Form S-3 (333-103451) and Form S-8 (333-58817, 333-50289 and 333-50205)) of Cal Dive International, Inc. of our report dated November 11, 2003 relating to the unaudited consolidated balance sheet of Cal Dive International, Inc. as of September 30, 2003 and the related unaudited consolidated statements of operations for the three-month and nine-month periods ended September 30, 2003 and 2002, and the consolidated statements of cash flows for the nine-month periods ended September 30, 2003 and 2002, that are included in its Form 10-Q for the quarter ended September 30, 2003. Very truly yours, /s/ Ernst & Young LLP Houston, Texas