diff --git a/Source/Core/Core/Config/MainSettings.cpp b/Source/Core/Core/Config/MainSettings.cpp
index a45c014262..defebcd426 100644
--- a/Source/Core/Core/Config/MainSettings.cpp
+++ b/Source/Core/Core/Config/MainSettings.cpp
@@ -117,6 +117,8 @@ const Info<ExpansionInterface::EXIDeviceType> MAIN_SLOT_B{{System::Main, "Core",
                                                           ExpansionInterface::EXIDeviceType::None};
 const Info<ExpansionInterface::EXIDeviceType> MAIN_SERIAL_PORT_1{
     {System::Main, "Core", "SerialPort1"}, ExpansionInterface::EXIDeviceType::None};
+const Info<ExpansionInterface::EXIDeviceType> MAIN_SERIAL_PORT_2{
+    {System::Main, "Core", "SerialPort2"}, ExpansionInterface::EXIDeviceType::None};
 
 const Info<ExpansionInterface::EXIDeviceType>& GetInfoForEXIDevice(ExpansionInterface::Slot slot)
 {
@@ -126,6 +128,7 @@ const Info<ExpansionInterface::EXIDeviceType>& GetInfoForEXIDevice(ExpansionInte
           &MAIN_SLOT_A,
           &MAIN_SLOT_B,
           &MAIN_SERIAL_PORT_1,
+          &MAIN_SERIAL_PORT_2,
       };
   return *infos[slot];
 }
diff --git a/Source/Core/Core/Config/MainSettings.h b/Source/Core/Core/Config/MainSettings.h
index d7e78bf6e9..a1d334bc18 100644
--- a/Source/Core/Core/Config/MainSettings.h
+++ b/Source/Core/Core/Config/MainSettings.h
@@ -90,6 +90,7 @@ extern const Info<int> MAIN_MEMORY_CARD_SIZE;
 extern const Info<ExpansionInterface::EXIDeviceType> MAIN_SLOT_A;
 extern const Info<ExpansionInterface::EXIDeviceType> MAIN_SLOT_B;
 extern const Info<ExpansionInterface::EXIDeviceType> MAIN_SERIAL_PORT_1;
+extern const Info<ExpansionInterface::EXIDeviceType> MAIN_SERIAL_PORT_2;
 const Info<ExpansionInterface::EXIDeviceType>& GetInfoForEXIDevice(ExpansionInterface::Slot slot);
 extern const Info<std::string> MAIN_BBA_MAC;
 extern const Info<std::string> MAIN_BBA_XLINK_IP;
diff --git a/Source/Core/Core/HW/EXI/EXI.cpp b/Source/Core/Core/HW/EXI/EXI.cpp
index fd371fa076..303191c574 100644
--- a/Source/Core/Core/HW/EXI/EXI.cpp
+++ b/Source/Core/Core/HW/EXI/EXI.cpp
@@ -76,6 +76,8 @@ u8 SlotToEXIChannel(Slot slot)
     return 1;
   case Slot::SP1:
     return 0;
+  case Slot::SP2:
+    return 2;
   default:
     PanicAlertFmt("Unhandled slot {}", slot);
     return 0;
@@ -92,6 +94,8 @@ u8 SlotToEXIDevice(Slot slot)
     return 0;
   case Slot::SP1:
     return 2;
+  case Slot::SP2:
+    return 0;
   default:
     PanicAlertFmt("Unhandled slot {}", slot);
     return 0;
@@ -143,7 +147,8 @@ void ExpansionInterfaceManager::Init(const Sram* override_sram)
   m_channels[0]->AddDevice(EXIDeviceType::MaskROM, 1);
   m_channels[SlotToEXIChannel(Slot::SP1)]->AddDevice(Config::Get(Config::MAIN_SERIAL_PORT_1),
                                                      SlotToEXIDevice(Slot::SP1));
-  m_channels[2]->AddDevice(EXIDeviceType::AD16, 0);
+  m_channels[SlotToEXIChannel(Slot::SP2)]->AddDevice(Config::Get(Config::MAIN_SERIAL_PORT_2),
+                                                     SlotToEXIDevice(Slot::SP2));
 
   m_event_type_change_device = core_timing.RegisterEvent("ChangeEXIDevice", ChangeDeviceCallback);
   m_event_type_update_interrupts =
diff --git a/Source/Core/Core/HW/EXI/EXI.h b/Source/Core/Core/HW/EXI/EXI.h
index a4f2b899d0..7ded905b98 100644
--- a/Source/Core/Core/HW/EXI/EXI.h
+++ b/Source/Core/Core/HW/EXI/EXI.h
@@ -44,11 +44,12 @@ enum class Slot : int
   A,
   B,
   SP1,
+  SP2,
 };
 // Note: using auto here results in a false warning on GCC
 // See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80351
-constexpr std::initializer_list<Slot> SLOTS = {Slot::A, Slot::B, Slot::SP1};
-constexpr auto MAX_SLOT = Slot::SP1;
+constexpr std::initializer_list<Slot> SLOTS = {Slot::A, Slot::B, Slot::SP1, Slot::SP2};
+constexpr auto MAX_SLOT = Slot::SP2;
 constexpr std::initializer_list<Slot> MEMCARD_SLOTS = {Slot::A, Slot::B};
 constexpr auto MAX_MEMCARD_SLOT = Slot::B;
 constexpr bool IsMemcardSlot(Slot slot)
@@ -106,5 +107,5 @@ private:
 template <>
 struct fmt::formatter<ExpansionInterface::Slot> : EnumFormatter<ExpansionInterface::MAX_SLOT>
 {
-  constexpr formatter() : EnumFormatter({"Slot A", "Slot B", "Serial Port 1"}) {}
+  constexpr formatter() : EnumFormatter({"Slot A", "Slot B", "Serial Port 1", "Serial Port 2"}) {}
 };
diff --git a/Source/Core/Core/NetPlayServer.cpp b/Source/Core/Core/NetPlayServer.cpp
index 0044ce903e..e592d97f5f 100644
--- a/Source/Core/Core/NetPlayServer.cpp
+++ b/Source/Core/Core/NetPlayServer.cpp
@@ -1378,6 +1378,11 @@ bool NetPlayServer::SetupNetSettings()
       // There's no way the BBA is going to sync, disable it
       device = ExpansionInterface::EXIDeviceType::None;
     }
+    else if (slot == ExpansionInterface::Slot::SP2)
+    {
+      // SD cards probably won't sync either
+      device = ExpansionInterface::EXIDeviceType::None;
+    }
     else
     {
       device = Config::Get(Config::GetInfoForEXIDevice(slot));
diff --git a/Source/Core/DolphinQt/Settings/GameCubePane.cpp b/Source/Core/DolphinQt/Settings/GameCubePane.cpp
index 9d38cb78f7..199ac51e73 100644
--- a/Source/Core/DolphinQt/Settings/GameCubePane.cpp
+++ b/Source/Core/DolphinQt/Settings/GameCubePane.cpp
@@ -158,6 +158,14 @@ void GameCubePane::CreateWidgets()
                                                           static_cast<int>(device));
   }
 
+  // Add SP2 devices
+  for (const auto device :
+       {EXIDeviceType::None, EXIDeviceType::Dummy, EXIDeviceType::AD16, EXIDeviceType::SD})
+  {
+    m_slot_combos[ExpansionInterface::Slot::SP2]->addItem(tr(fmt::format("{:n}", device).c_str()),
+                                                          static_cast<int>(device));
+  }
+
   {
     int row = 0;
     device_layout->addWidget(new QLabel(tr("Slot A:")), row, 0);
@@ -191,6 +199,11 @@ void GameCubePane::CreateWidgets()
     device_layout->addWidget(new QLabel(tr("SP1:")), row, 0);
     device_layout->addWidget(m_slot_combos[ExpansionInterface::Slot::SP1], row, 1);
     device_layout->addWidget(m_slot_buttons[ExpansionInterface::Slot::SP1], row, 2);
+
+    ++row;
+    device_layout->addWidget(new QLabel(tr("SP2:")), row, 0);
+    device_layout->addWidget(m_slot_combos[ExpansionInterface::Slot::SP2], row, 1);
+    device_layout->addWidget(m_slot_buttons[ExpansionInterface::Slot::SP2], row, 2);
   }
 
 #ifdef HAS_LIBMGBA
@@ -358,6 +371,9 @@ void GameCubePane::UpdateButton(ExpansionInterface::Slot slot)
                   device == ExpansionInterface::EXIDeviceType::EthernetBuiltIn ||
                   device == ExpansionInterface::EXIDeviceType::ModemTapServer);
     break;
+  case ExpansionInterface::Slot::SP2:
+    has_config = false;  // TODO
+    break;
   }
 
   m_slot_buttons[slot]->setEnabled(has_config);