diff --git a/PKHeX.Core/Saves/Substructures/Gen3/SecretBase3.cs b/PKHeX.Core/Saves/Substructures/Gen3/SecretBase3.cs
new file mode 100644
index 000000000..2be1f10b4
--- /dev/null
+++ b/PKHeX.Core/Saves/Substructures/Gen3/SecretBase3.cs
@@ -0,0 +1,71 @@
+using System;
+using System.Linq;
+
+namespace PKHeX.Core
+{
+    public class SecretBase3
+    {
+        private readonly byte[] Data;
+        private readonly int Offset;
+        private bool Japanese => Language == (int) LanguageID.Japanese;
+
+        public SecretBase3(byte[] data, int offset)
+        {
+            Data = data;
+            Offset = offset;
+        }
+
+        public int SecretBaseLocation { get => Data[Offset + 0]; set => Data[Offset + 0] = (byte) value; }
+        public int OT_Gender
+        {
+            get => (Data[Offset + 1] >> 4) & 1;
+            set => Data[Offset + 1] = (byte) ((Data[Offset + 1] & 0xEF) | (value & 1) << 4);
+        }
+
+        public string OT_Name
+        {
+            get => StringConverter.GetString3(Data, Offset + 2, 7, Japanese);
+            set => StringConverter.SetString3(value, 7, Japanese, 7).CopyTo(Data, Offset + 2);
+        }
+        public uint OT_ID
+        {
+            get => BitConverter.ToUInt32(Data, Offset + 9);
+            set => BitConverter.GetBytes(value).CopyTo(Data, Offset + 9);
+        }
+        public int OT_Class { get => Data[Offset + 9]; set => Data[Offset + 9] = (byte) value; }
+        public int Language { get => Data[Offset + 0x0D]; set => Data[Offset + 0x0D] = (byte)value; }
+        public int _E       { get => Data[Offset + 0x0E]; set => Data[Offset + 0x0E] = (byte)value; }
+        public int _F       { get => Data[Offset + 0x0F]; set => Data[Offset + 0x0F] = (byte)value; }
+        public int _10      { get => Data[Offset + 0x10]; set => Data[Offset + 0x10] = (byte)value; }
+        public int _11      { get => Data[Offset + 0x11]; set => Data[Offset + 0x11] = (byte)value; }
+
+        public byte[] Decorations
+        {
+            get => Data.Skip(Offset + 0x12).Take(0x10).ToArray();
+            set => value.CopyTo(Data, Offset + 0x12);
+        }
+        public byte[] DecorationCoordinates
+        {
+            get => Data.Skip(Offset + 0x22).Take(0x10).ToArray();
+            set => value.CopyTo(Data, Offset + 0x22);
+        }
+
+        public SecretBase3Team Team
+        {
+            get => new SecretBase3Team(Data.Skip(Offset + 50).Take(72).ToArray());
+            set => value.Write().CopyTo(Data, Offset + 50);
+        }
+
+        public int TID
+        {
+            get => (ushort)OT_ID;
+            set => OT_ID = (ushort)(SID | (ushort)value);
+        }
+
+        public int SID
+        {
+            get => (ushort)OT_ID >> 8;
+            set => OT_ID = (ushort)(((ushort)value << 16) | TID);
+        }
+    }
+}
diff --git a/PKHeX.Core/Saves/Substructures/Gen3/SecretBase3PKM.cs b/PKHeX.Core/Saves/Substructures/Gen3/SecretBase3PKM.cs
new file mode 100644
index 000000000..54f44f4d0
--- /dev/null
+++ b/PKHeX.Core/Saves/Substructures/Gen3/SecretBase3PKM.cs
@@ -0,0 +1,32 @@
+using System;
+using System.Linq;
+
+namespace PKHeX.Core
+{
+    public class SecretBase3PKM
+    {
+        public uint PID { get; set; }
+        public int Move1 { get; set; }
+        public int Move2 { get; set; }
+        public int Move3 { get; set; }
+        public int Move4 { get; set; }
+        public int Species { get; set; }
+        public int HeldItem { get; set; }
+        public int Level { get; set; }
+        public int EVAll { get; set; }
+        public int[] Moves => new[] { Move1, Move2, Move3, Move4 };
+
+        public string Summary
+        {
+            get
+            {
+                var first = $"{Species:000} - {GameInfo.Strings.Species[Species]}";
+                if (HeldItem != 0)
+                    first += $"@ {GameInfo.Strings.Item[HeldItem]}";
+                var second = $"Moves: {string.Join(" / ", Moves.Select(z => GameInfo.Strings.Move[z]))}";
+                var third = $"Level: {Level}, EVs: {EVAll}, PID: {PID}";
+                return first + Environment.NewLine + second + Environment.NewLine + third;
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/PKHeX.Core/Saves/Substructures/Gen3/SecretBase3Team.cs b/PKHeX.Core/Saves/Substructures/Gen3/SecretBase3Team.cs
new file mode 100644
index 000000000..3796a7582
--- /dev/null
+++ b/PKHeX.Core/Saves/Substructures/Gen3/SecretBase3Team.cs
@@ -0,0 +1,68 @@
+using System;
+
+namespace PKHeX.Core
+{
+    public class SecretBase3Team
+    {
+        private const int O_PID = 0;
+        private const int O_Moves = 0x18;
+        private const int O_Species = 0x24;
+        private const int O_Item = 0x30;
+        private const int O_Level = 0x3C;
+        private const int O_EV = 0x42;
+
+        private static int GetOffsetPID(int i) => O_PID + (i * 4);
+        private static int GetOffsetMove(int i, int move) => O_Moves + (i * 8) + (move * 2);
+        private static int GetOffsetSpecies(int i) => O_Species + (i * 2);
+        private static int GetOffsetItem(int i) => O_Item + (i * 2);
+
+        public readonly SecretBase3PKM[] Team;
+        private readonly byte[] Data;
+        public SecretBase3Team(byte[] data)
+        {
+            Team = new SecretBase3PKM[6];
+            for (int i = 0; i < Team.Length; i++)
+                Team[i] = GetPKM(i);
+            Data = data;
+        }
+
+        public byte[] Write()
+        {
+            for (int i = 0; i < Team.Length; i++)
+                SetPKM(i);
+            return Data;
+        }
+
+        private SecretBase3PKM GetPKM(int i)
+        {
+            return new SecretBase3PKM
+            {
+                PID = BitConverter.ToUInt32(Data, GetOffsetPID(i)),
+                Species = BitConverter.ToUInt16(Data, GetOffsetSpecies(i)),
+                HeldItem = BitConverter.ToUInt16(Data, GetOffsetItem(i)),
+                Move1 = BitConverter.ToUInt16(Data, GetOffsetMove(i, 0)),
+                Move2 = BitConverter.ToUInt16(Data, GetOffsetMove(i, 1)),
+                Move3 = BitConverter.ToUInt16(Data, GetOffsetMove(i, 2)),
+                Move4 = BitConverter.ToUInt16(Data, GetOffsetMove(i, 3)),
+                Level = Data[O_Level + i],
+                EVAll = Data[O_EV + i],
+            };
+        }
+
+        private void SetPKM(int i)
+        {
+            var pk = Team[i];
+            BitConverter.GetBytes((uint) pk.PID).CopyTo(Data, GetOffsetPID(i));
+            BitConverter.GetBytes((ushort)pk.Species).CopyTo(Data, GetOffsetSpecies(i));
+            BitConverter.GetBytes((ushort)pk.HeldItem).CopyTo(Data, GetOffsetItem(i));
+            BitConverter.GetBytes((ushort)pk.Move1).CopyTo(Data, GetOffsetMove(i, 0));
+            BitConverter.GetBytes((ushort)pk.Move2).CopyTo(Data, GetOffsetMove(i, 1));
+            BitConverter.GetBytes((ushort)pk.Move3).CopyTo(Data, GetOffsetMove(i, 2));
+            BitConverter.GetBytes((ushort)pk.Move4).CopyTo(Data, GetOffsetMove(i, 3));
+            Data[O_Level + i] = (byte) pk.Level;
+            Data[O_EV + i] = (byte) pk.EVAll;
+
+            BitConverter.GetBytes((uint) pk.PID).CopyTo(Data, GetOffsetPID(i));
+        }
+    }
+}
\ No newline at end of file