In-beam ␥-ray spectroscopy of 188 Pb has been carried out using Gammasphere. Time-correlated ␥-␥ coincidence methods have allowed the identification of new structures above and below the two-particle isomeric states. The detailed decay of the proposed K =8 − , 1 s isomer has been established, together with a rotational band based on the isomer. Both decay and band properties confirm the association with a prolate deformation and the two-quasineutron 9 / 2 + ͓624͔ 7/2 − ͓514͔ configuration. The band structure identified above the 11 − isomer from the two-proton configuration 9 / 2 − ͓505͔ 13/ 2 + ͓606͔ has a moment of inertia similar to those of the bands known in heavier isotopes and to the one-quasiproton components, but the perturbations and in-band properties are not as expected for a simple, symmetric oblate deformation. This structure is fed by a ͑19 − ͒ isomer. Possible configurations for this and other multiquasiparticle states are discussed in the context of multi-quasiparticle calculations for coexisting deformations. Low-spin structures populated partly from the decay of the 8 − isomer have also been identified. Several of these may be associated with proposed excited 0 + states. Their properties, including yrare-yrast E0 decays and gamma-ray branching ratios, are analyzed using band-mixing models. These and other analyses support a shape coexistence scenario, with some qualifications.