The disclosure relates to detecting phase slips that may occur in a multi-lane serial datalink. Phase slips may occur when a lane experiences lane skew, which may introduce a phase slip with respect to another lane. To detect phase slippage, the system may select a reference lane from among the lanes. The system may generate a pre-deskew delta value based on a difference between the FIFO filling level of the reference lane before a deskew and the FIFO filling level of a second lane before the deskew. The system may generate a post-deskew delta value based on a difference between the FIFO filling level of the reference lane after the deskew and the FIFO filling level of the second lane after the deskew. The system may use a difference between the post-deskew delta and the pre-deskew delta to detect phase slip on the second lane relative to the reference lane.