A method of connecting an in-line subsea structure to a pipe-in-pipe (PIP) pipeline for laying in a marine environment, the PIP pipeline comprising at least metal inner and outer pipes and an annular space thereinbetween, the method comprising at least the steps of: (i) providing the PIP pipeline having either: (a) one or more PIP connectors having a first connector end comprising inner and outer longitudinal collars corresponding in circumference to the circumferences of the inner and outer pipes of the PIP pipeline, and welded to the PIP pipeline, and a second connector end having a coupling portion coupling with a pipeline section and a machined portion configured to match and connect with a complementary portal or bore of the in-line subsea structure . or (b) one or more joining assemblies comprising at least first and second of the pipe-in-pipe (PIP) connectors defined in (a) above and a coupling between the coupling portions of the second connector ends of the first and second connectors, said coupling able to be decoupled from the coupling portions of the second connector ends between two said PIP sections, or (c) both; (ii) decoupling the coupling of at least one second connector end of a PIP connector to provide the machined portion of the PIP connector; and (iii) connecting the in-line subsea structure onto the machined portion of the PIP connector to connect the in-line subsea structure to the PIP pipeline. (i) providing the PIP pipeline having either: (a) one or more PIP connectors having a first connector end comprising inner and outer longitudinal collars corresponding in circumference to the circumferences of the inner and outer pipes of the PIP pipeline, and welded to the PIP pipeline, and a second connector end having a coupling portion coupling with a pipeline section and a machined portion configured to match and connect with a complementary portal or bore of the in-line subsea structure . or (b) one or more joining assemblies comprising at least first and second of the pipe-in-pipe (PIP) connectors defined in (a) above and a coupling between the coupling portions of the second connector ends of the first and second connectors, said coupling able to be decoupled from the coupling portions of the second connector ends between two said PIP sections, or (c) both; (a) one or more PIP connectors having a first connector end comprising inner and outer longitudinal collars corresponding in circumference to the circumferences of the inner and outer pipes of the PIP pipeline, and welded to the PIP pipeline, and a second connector end having a coupling portion coupling with a pipeline section and a machined portion configured to match and connect with a complementary portal or bore of the in-line subsea structure . or (b) one or more joining assemblies comprising at least first and second of the pipe-in-pipe (PIP) connectors defined in (a) above and a coupling between the coupling portions of the second connector ends of the first and second connectors, said coupling able to be decoupled from the coupling portions of the second connector ends between two said PIP sections, or (c) both; (ii) decoupling the coupling of at least one second connector end of a PIP connector to provide the machined portion of the PIP connector; and (iii) connecting the in-line subsea structure onto the machined portion of the PIP connector to connect the in-line subsea structure to the PIP pipeline. <EOS>