G protein-coupled receptors in intracellular organelles can be activated in response to membrane permeant ligands, which contributes to the diversity and specificity of agonist action. The opioid receptors (ORs) provide a striking example, where small molecule opioid drugs activate ORs in the Golgi apparatus within seconds of drug addition. To date, our knowledge on the signaling of intracellular GPCRs remains incomplete and it is unknown if the downstream events triggered by ORs in plasma membrane and Golgi apparatus differ. To address this gap, we analyzed OR-mediated phosphorylation changes in cells treated with SNC80 (signaling control) or ICI-SNC80 (Golgi-restricted signaling) for 5 min or 25 min. We show that OR activation in the plasma membrane or Golgi apparatus have strikingly different downstream effects on protein phosphorylation. The study delineates OR signal transduction with unprecedented resolution and reveals that the subcellular location defines the signaling effect promoted by opioid drugs.