Dissolved　organic　carbon　(DOC)　in　coastal　waters　is　integral　to　biogeochemical　cycling,　but　global　and　regional　drivers　of　DOC　are　still　uncertain.　In　this　study　we　explored　spatial　and　temporal　differences　in　DOC　concentrations　and　stocks　across　the　global　coastal　ocean,　and　how　these　relate　to　temperature　and　salinity.　We　estimated　a　global　median　coastal　DOC　stock　of　3.15　Pg　C　(interquartile　range　(IQR)　=　0.85　Pg　C),　with　median　DOC　concentrations　being　2.2　times　higher　than　in　open　ocean　surface　waters.　Globally　and　seasonally,　salinity　was　the　main　driver　of　DOC　with　concentrations　correlated　negatively　with　salinity,　without　a　clear　relationship　to　temperature.　DOC　concentrations　and　stocks　varied　with　region　and　season　and　this　pattern　is　likely　driven　by　riverine　inputs　of　DOC　and　nutrients　that　stimulate　coastal　phytoplankton　production.　Temporally,　high　DOC　concentrations　occurred　mainly　in　months　with　high　freshwater　input,　with　some　exceptions　such　as　in　Eastern　Boundary　Current　margins　where　peaks　are　related　to　primary　production　stimulated　by　nutrients　upwelled　from　the　adjacent　ocean.　No　spatial　trend　between　DOC　and　temperature　was　apparent,　but　many　regions　(19　out　of　25)　had　aligned　peaks　of　seasonal　temperature　and　DOC,　related　to　increased　phytoplankton　production　and　vertical　stratification　at　high　temperatures.　Links　of　coastal　DOC　with　salinity　and　temperature　highlight　the　potential　for　anthropogenic　impacts　to　alter　coastal　DOC　concentration　and　composition,　and　thereby　ecosystem　status.