Almost always attributive:
越洋电话 (yuèyáng diànhuà, 'transoceanic call'),
越洋航班 (yuèyáng hángbān, 'transoceanic flight'),
越洋光缆 (yuèyáng guānglǎn, 'transoceanic fiber cable').
越洋电话 was a meaningful phrase in the era when international calls were rare and expensive — today most uses lean toward shipping, aviation, or undersea cables.
