diff --git a/osu.Game.Tests/Mods/ModUtilsTest.cs b/osu.Game.Tests/Mods/ModUtilsTest.cs
index 4c126f0a3b..6c9dddf51f 100644
--- a/osu.Game.Tests/Mods/ModUtilsTest.cs
+++ b/osu.Game.Tests/Mods/ModUtilsTest.cs
@@ -137,33 +137,137 @@ namespace osu.Game.Tests.Mods
             // incompatible pair.
             new object[]
             {
-                new Mod[] { new OsuModDoubleTime(), new OsuModHalfTime() },
-                new[] { typeof(OsuModDoubleTime), typeof(OsuModHalfTime) }
+                new Mod[] { new OsuModHidden(), new OsuModApproachDifferent() },
+                new[] { typeof(OsuModHidden), typeof(OsuModApproachDifferent) }
             },
             // incompatible pair with derived class.
             new object[]
             {
-                new Mod[] { new OsuModNightcore(), new OsuModHalfTime() },
-                new[] { typeof(OsuModNightcore), typeof(OsuModHalfTime) }
+                new Mod[] { new OsuModDeflate(), new OsuModApproachDifferent() },
+                new[] { typeof(OsuModDeflate), typeof(OsuModApproachDifferent) }
             },
             // system mod.
             new object[]
             {
-                new Mod[] { new OsuModDoubleTime(), new OsuModTouchDevice() },
+                new Mod[] { new OsuModHidden(), new OsuModTouchDevice() },
                 new[] { typeof(OsuModTouchDevice) }
             },
             // multi mod.
             new object[]
             {
-                new Mod[] { new MultiMod(new OsuModHalfTime()), new OsuModDaycore() },
+                new Mod[] { new MultiMod(new OsuModSuddenDeath(), new OsuModPerfect()) },
                 new[] { typeof(MultiMod) }
             },
+            // invalid multiplayer mod is valid for local.
+            new object[]
+            {
+                new Mod[] { new OsuModHidden(), new InvalidMultiplayerMod() },
+                null
+            },
+            // invalid free mod is valid for local.
+            new object[]
+            {
+                new Mod[] { new OsuModHidden(), new InvalidMultiplayerFreeMod() },
+                null
+            },
             // valid pair.
             new object[]
             {
-                new Mod[] { new OsuModDoubleTime(), new OsuModHardRock() },
+                new Mod[] { new OsuModHidden(), new OsuModHardRock() },
                 null
-            }
+            },
+        };
+
+        private static readonly object[] invalid_multiplayer_mod_test_scenarios =
+        {
+            // incompatible pair.
+            new object[]
+            {
+                new Mod[] { new OsuModHidden(), new OsuModApproachDifferent() },
+                new[] { typeof(OsuModHidden), typeof(OsuModApproachDifferent) }
+            },
+            // incompatible pair with derived class.
+            new object[]
+            {
+                new Mod[] { new OsuModDeflate(), new OsuModApproachDifferent() },
+                new[] { typeof(OsuModDeflate), typeof(OsuModApproachDifferent) }
+            },
+            // system mod.
+            new object[]
+            {
+                new Mod[] { new OsuModHidden(), new OsuModTouchDevice() },
+                new[] { typeof(OsuModTouchDevice) }
+            },
+            // multi mod.
+            new object[]
+            {
+                new Mod[] { new MultiMod(new OsuModSuddenDeath(), new OsuModPerfect()) },
+                new[] { typeof(MultiMod) }
+            },
+            // invalid multiplayer mod.
+            new object[]
+            {
+                new Mod[] { new OsuModHidden(), new InvalidMultiplayerMod() },
+                new[] { typeof(InvalidMultiplayerMod) }
+            },
+            // invalid free mod is valid for multiplayer global.
+            new object[]
+            {
+                new Mod[] { new OsuModHidden(), new InvalidMultiplayerFreeMod() },
+                null
+            },
+            // valid pair.
+            new object[]
+            {
+                new Mod[] { new OsuModHidden(), new OsuModHardRock() },
+                null
+            },
+        };
+
+        private static readonly object[] invalid_free_mod_test_scenarios =
+        {
+            // system mod.
+            new object[]
+            {
+                new Mod[] { new OsuModHidden(), new OsuModTouchDevice() },
+                new[] { typeof(OsuModTouchDevice) }
+            },
+            // multi mod.
+            new object[]
+            {
+                new Mod[] { new MultiMod(new OsuModSuddenDeath(), new OsuModPerfect()) },
+                new[] { typeof(MultiMod) }
+            },
+            // invalid multiplayer mod.
+            new object[]
+            {
+                new Mod[] { new OsuModHidden(), new InvalidMultiplayerMod() },
+                new[] { typeof(InvalidMultiplayerMod) }
+            },
+            // invalid free mod.
+            new object[]
+            {
+                new Mod[] { new OsuModHidden(), new InvalidMultiplayerFreeMod() },
+                new[] { typeof(InvalidMultiplayerFreeMod) }
+            },
+            // incompatible pair is valid for free mods.
+            new object[]
+            {
+                new Mod[] { new OsuModHidden(), new OsuModApproachDifferent() },
+                null,
+            },
+            // incompatible pair with derived class is valid for free mods.
+            new object[]
+            {
+                new Mod[] { new OsuModDeflate(), new OsuModSpinIn() },
+                null,
+            },
+            // valid pair.
+            new object[]
+            {
+                new Mod[] { new OsuModHidden(), new OsuModHardRock() },
+                null
+            },
         };
 
         [TestCaseSource(nameof(invalid_mod_test_scenarios))]
@@ -179,6 +283,32 @@ namespace osu.Game.Tests.Mods
                 Assert.That(invalid.Select(t => t.GetType()), Is.EquivalentTo(expectedInvalid));
         }
 
+        [TestCaseSource(nameof(invalid_multiplayer_mod_test_scenarios))]
+        public void TestInvalidMultiplayerModScenarios(Mod[] inputMods, Type[] expectedInvalid)
+        {
+            bool isValid = ModUtils.CheckValidRequiredModsForMultiplayer(inputMods, out var invalid);
+
+            Assert.That(isValid, Is.EqualTo(expectedInvalid == null));
+
+            if (isValid)
+                Assert.IsNull(invalid);
+            else
+                Assert.That(invalid.Select(t => t.GetType()), Is.EquivalentTo(expectedInvalid));
+        }
+
+        [TestCaseSource(nameof(invalid_free_mod_test_scenarios))]
+        public void TestInvalidFreeModScenarios(Mod[] inputMods, Type[] expectedInvalid)
+        {
+            bool isValid = ModUtils.CheckValidFreeModsForMultiplayer(inputMods, out var invalid);
+
+            Assert.That(isValid, Is.EqualTo(expectedInvalid == null));
+
+            if (isValid)
+                Assert.IsNull(invalid);
+            else
+                Assert.That(invalid.Select(t => t.GetType()), Is.EquivalentTo(expectedInvalid));
+        }
+
         public abstract class CustomMod1 : Mod, IModCompatibilitySpecification
         {
         }
@@ -187,6 +317,27 @@ namespace osu.Game.Tests.Mods
         {
         }
 
+        public class InvalidMultiplayerMod : Mod
+        {
+            public override string Name => string.Empty;
+            public override string Description => string.Empty;
+            public override string Acronym => string.Empty;
+            public override double ScoreMultiplier => 1;
+            public override bool HasImplementation => true;
+            public override bool ValidForMultiplayer => false;
+            public override bool ValidForMultiplayerAsFreeMod => false;
+        }
+
+        private class InvalidMultiplayerFreeMod : Mod
+        {
+            public override string Name => string.Empty;
+            public override string Description => string.Empty;
+            public override string Acronym => string.Empty;
+            public override double ScoreMultiplier => 1;
+            public override bool HasImplementation => true;
+            public override bool ValidForMultiplayerAsFreeMod => false;
+        }
+
         public interface IModCompatibilitySpecification
         {
         }
diff --git a/osu.Game/Rulesets/Mods/IMod.cs b/osu.Game/Rulesets/Mods/IMod.cs
index d5d1de91de..30fa1ea8cb 100644
--- a/osu.Game/Rulesets/Mods/IMod.cs
+++ b/osu.Game/Rulesets/Mods/IMod.cs
@@ -39,6 +39,18 @@ namespace osu.Game.Rulesets.Mods
         /// </summary>
         bool UserPlayable { get; }
 
+        /// <summary>
+        /// Whether this mod is valid for multiplayer matches.
+        /// Should be <c>false</c> for mods that make gameplay duration dependent on user input (e.g. <see cref="ModAdaptiveSpeed"/>).
+        /// </summary>
+        bool ValidForMultiplayer { get; }
+
+        /// <summary>
+        /// Whether this mod is valid as a free mod in multiplayer matches.
+        /// Should be <c>false</c> for mods that affect the gameplay duration (e.g. <see cref="ModRateAdjust"/> and <see cref="ModTimeRamp"/>).
+        /// </summary>
+        bool ValidForMultiplayerAsFreeMod { get; }
+
         /// <summary>
         /// Create a fresh <see cref="Mod"/> instance based on this mod.
         /// </summary>
diff --git a/osu.Game/Rulesets/Mods/Mod.cs b/osu.Game/Rulesets/Mods/Mod.cs
index b2d4be54ce..af1550f8a9 100644
--- a/osu.Game/Rulesets/Mods/Mod.cs
+++ b/osu.Game/Rulesets/Mods/Mod.cs
@@ -94,6 +94,12 @@ namespace osu.Game.Rulesets.Mods
         [JsonIgnore]
         public virtual bool UserPlayable => true;
 
+        [JsonIgnore]
+        public virtual bool ValidForMultiplayer => true;
+
+        [JsonIgnore]
+        public virtual bool ValidForMultiplayerAsFreeMod => true;
+
         [Obsolete("Going forward, the concept of \"ranked\" doesn't exist. The only exceptions are automation mods, which should now override and set UserPlayable to false.")] // Can be removed 20211009
         public virtual bool Ranked => false;
 
diff --git a/osu.Game/Rulesets/Mods/ModAdaptiveSpeed.cs b/osu.Game/Rulesets/Mods/ModAdaptiveSpeed.cs
index 1115b95e6f..93251f7b2d 100644
--- a/osu.Game/Rulesets/Mods/ModAdaptiveSpeed.cs
+++ b/osu.Game/Rulesets/Mods/ModAdaptiveSpeed.cs
@@ -31,6 +31,9 @@ namespace osu.Game.Rulesets.Mods
 
         public override double ScoreMultiplier => 1;
 
+        public override bool ValidForMultiplayer => false;
+        public override bool ValidForMultiplayerAsFreeMod => false;
+
         public override Type[] IncompatibleMods => new[] { typeof(ModRateAdjust), typeof(ModTimeRamp) };
 
         [SettingSource("Initial rate", "The starting speed of the track")]
diff --git a/osu.Game/Rulesets/Mods/ModAutoplay.cs b/osu.Game/Rulesets/Mods/ModAutoplay.cs
index 87dc627b19..0ebe11b393 100644
--- a/osu.Game/Rulesets/Mods/ModAutoplay.cs
+++ b/osu.Game/Rulesets/Mods/ModAutoplay.cs
@@ -25,6 +25,8 @@ namespace osu.Game.Rulesets.Mods
         public bool RestartOnFail => false;
 
         public override bool UserPlayable => false;
+        public override bool ValidForMultiplayer => false;
+        public override bool ValidForMultiplayerAsFreeMod => false;
 
         public override Type[] IncompatibleMods => new[] { typeof(ModCinema), typeof(ModRelax), typeof(ModFailCondition), typeof(ModNoFail) };
 
diff --git a/osu.Game/Rulesets/Mods/ModRateAdjust.cs b/osu.Game/Rulesets/Mods/ModRateAdjust.cs
index 88fb609c07..05953f903f 100644
--- a/osu.Game/Rulesets/Mods/ModRateAdjust.cs
+++ b/osu.Game/Rulesets/Mods/ModRateAdjust.cs
@@ -11,6 +11,8 @@ namespace osu.Game.Rulesets.Mods
 {
     public abstract class ModRateAdjust : Mod, IApplicableToRate
     {
+        public override bool ValidForMultiplayerAsFreeMod => false;
+
         public abstract BindableNumber<double> SpeedChange { get; }
 
         public virtual void ApplyToTrack(ITrack track)
diff --git a/osu.Game/Rulesets/Mods/ModTimeRamp.cs b/osu.Game/Rulesets/Mods/ModTimeRamp.cs
index b6b2decede..fe6d54332c 100644
--- a/osu.Game/Rulesets/Mods/ModTimeRamp.cs
+++ b/osu.Game/Rulesets/Mods/ModTimeRamp.cs
@@ -30,6 +30,8 @@ namespace osu.Game.Rulesets.Mods
         [SettingSource("Adjust pitch", "Should pitch be adjusted with speed")]
         public abstract BindableBool AdjustPitch { get; }
 
+        public override bool ValidForMultiplayerAsFreeMod => false;
+
         public override Type[] IncompatibleMods => new[] { typeof(ModRateAdjust), typeof(ModAdaptiveSpeed) };
 
         public override string SettingDescription => $"{InitialRate.Value:N2}x to {FinalRate.Value:N2}x";
diff --git a/osu.Game/Rulesets/Mods/UnknownMod.cs b/osu.Game/Rulesets/Mods/UnknownMod.cs
index b426386d7a..72de0ad653 100644
--- a/osu.Game/Rulesets/Mods/UnknownMod.cs
+++ b/osu.Game/Rulesets/Mods/UnknownMod.cs
@@ -16,6 +16,8 @@ namespace osu.Game.Rulesets.Mods
         public override double ScoreMultiplier => 0;
 
         public override bool UserPlayable => false;
+        public override bool ValidForMultiplayer => false;
+        public override bool ValidForMultiplayerAsFreeMod => false;
 
         public override ModType Type => ModType.System;
 
diff --git a/osu.Game/Screens/OnlinePlay/Multiplayer/MultiplayerMatchSongSelect.cs b/osu.Game/Screens/OnlinePlay/Multiplayer/MultiplayerMatchSongSelect.cs
index 848424bc76..929c3ee321 100644
--- a/osu.Game/Screens/OnlinePlay/Multiplayer/MultiplayerMatchSongSelect.cs
+++ b/osu.Game/Screens/OnlinePlay/Multiplayer/MultiplayerMatchSongSelect.cs
@@ -95,6 +95,8 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer
 
         protected override BeatmapDetailArea CreateBeatmapDetailArea() => new PlayBeatmapDetailArea();
 
-        protected override bool IsValidFreeMod(Mod mod) => base.IsValidFreeMod(mod) && !(mod is ModTimeRamp) && !(mod is ModRateAdjust);
+        protected override bool IsValidMod(Mod mod) => base.IsValidMod(mod) && mod.ValidForMultiplayer;
+
+        protected override bool IsValidFreeMod(Mod mod) => base.IsValidFreeMod(mod) && mod.ValidForMultiplayerAsFreeMod;
     }
 }
diff --git a/osu.Game/Utils/ModUtils.cs b/osu.Game/Utils/ModUtils.cs
index 8df44216b6..ea092a8ca3 100644
--- a/osu.Game/Utils/ModUtils.cs
+++ b/osu.Game/Utils/ModUtils.cs
@@ -106,22 +106,69 @@ namespace osu.Game.Utils
         }
 
         /// <summary>
-        /// Check the provided combination of mods are valid for a local gameplay session.
+        /// Checks that all <see cref="Mod"/>s in a combination are valid for a local gameplay session.
         /// </summary>
         /// <param name="mods">The mods to check.</param>
-        /// <param name="invalidMods">Invalid mods, if any were found. Can be null if all mods were valid.</param>
+        /// <param name="invalidMods">Invalid mods, if any were found. Will be null if all mods were valid.</param>
         /// <returns>Whether the input mods were all valid. If false, <paramref name="invalidMods"/> will contain all invalid entries.</returns>
         public static bool CheckValidForGameplay(IEnumerable<Mod> mods, [NotNullWhen(false)] out List<Mod>? invalidMods)
         {
             mods = mods.ToArray();
 
-            // exclude multi mods from compatibility checks.
-            // the loop below automatically marks all multi mods as not valid for gameplay anyway.
-            CheckCompatibleSet(mods.Where(m => !(m is MultiMod)), out invalidMods);
+            // checking compatibility of multi mods would try to flatten them and return incompatible mods.
+            // in gameplay context, we never want MultiMod selected in the first place, therefore check against it first.
+            if (!checkValid(mods, m => !(m is MultiMod), out invalidMods))
+                return false;
+
+            if (!CheckCompatibleSet(mods, out invalidMods))
+                return false;
+
+            return checkValid(mods, m => m.Type != ModType.System && m.HasImplementation, out invalidMods);
+        }
+
+        /// <summary>
+        /// Checks that all <see cref="Mod"/>s in a combination are valid as "required mods" in a multiplayer match session.
+        /// </summary>
+        /// <param name="mods">The mods to check.</param>
+        /// <param name="invalidMods">Invalid mods, if any were found. Will be null if all mods were valid.</param>
+        /// <returns>Whether the input mods were all valid. If false, <paramref name="invalidMods"/> will contain all invalid entries.</returns>
+        public static bool CheckValidRequiredModsForMultiplayer(IEnumerable<Mod> mods, [NotNullWhen(false)] out List<Mod>? invalidMods)
+        {
+            mods = mods.ToArray();
+
+            // checking compatibility of multi mods would try to flatten them and return incompatible mods.
+            // in gameplay context, we never want MultiMod selected in the first place, therefore check against it first.
+            if (!checkValid(mods, m => !(m is MultiMod), out invalidMods))
+                return false;
+
+            if (!CheckCompatibleSet(mods, out invalidMods))
+                return false;
+
+            return checkValid(mods, m => m.Type != ModType.System && m.HasImplementation && m.ValidForMultiplayer, out invalidMods);
+        }
+
+        /// <summary>
+        /// Checks that all <see cref="Mod"/>s in a combination are valid as "free mods" in a multiplayer match session.
+        /// </summary>
+        /// <remarks>
+        /// Note that this does not check compatibility between mods,
+        /// given that the passed mods are expected to be the ones to be allowed for the multiplayer match,
+        /// not to be confused with the list of mods the user currently has selected for the multiplayer match.
+        /// </remarks>
+        /// <param name="mods">The mods to check.</param>
+        /// <param name="invalidMods">Invalid mods, if any were found. Will be null if all mods were valid.</param>
+        /// <returns>Whether the input mods were all valid. If false, <paramref name="invalidMods"/> will contain all invalid entries.</returns>
+        public static bool CheckValidFreeModsForMultiplayer(IEnumerable<Mod> mods, [NotNullWhen(false)] out List<Mod>? invalidMods)
+            => checkValid(mods, m => m.Type != ModType.System && m.HasImplementation && m.ValidForMultiplayerAsFreeMod && !(m is MultiMod), out invalidMods);
+
+        private static bool checkValid(IEnumerable<Mod> mods, Predicate<Mod> valid, [NotNullWhen(false)] out List<Mod>? invalidMods)
+        {
+            mods = mods.ToArray();
+            invalidMods = null;
 
             foreach (var mod in mods)
             {
-                if (mod.Type == ModType.System || !mod.HasImplementation || mod is MultiMod)
+                if (!valid(mod))
                 {
                     invalidMods ??= new List<Mod>();
                     invalidMods.Add(mod);