diff --git a/config/formats.ts b/config/formats.ts
index c8ba02592e..be4b4c75e5 100644
--- a/config/formats.ts
+++ b/config/formats.ts
@@ -4100,7 +4100,7 @@ export const Formats: import('../sim/dex-formats').FormatList = [
 		mod: 'gen4',
 		team: 'random',
 		bestOfDefault: true,
-		ruleset: ['Obtainable', 'Sleep Clause Mod', 'HP Percentage Mod', 'Cancel Mod'],
+		ruleset: ['Standard'],
 	},
 	{
 		name: "[Gen 3] Random Battle",
@@ -4130,7 +4130,7 @@ export const Formats: import('../sim/dex-formats').FormatList = [
 		team: 'randomCC',
 		searchShow: false,
 		challengeShow: false,
-		ruleset: ['Obtainable', 'HP Percentage Mod', 'Cancel Mod', 'Desync Clause Mod', 'Sleep Clause Mod', 'Freeze Clause Mod'],
+		ruleset: ['Obtainable', 'Switch Priority Clause Mod', 'HP Percentage Mod', 'Cancel Mod', 'Sleep Clause Mod', 'Freeze Clause Mod'],
 	},
 	{
 		name: "[Gen 1] Hackmons Cup",
@@ -4139,7 +4139,7 @@ export const Formats: import('../sim/dex-formats').FormatList = [
 		team: 'randomHC',
 		searchShow: false,
 		challengeShow: false,
-		ruleset: ['HP Percentage Mod', 'Cancel Mod', 'Desync Clause Mod', 'Sleep Clause Mod', 'Freeze Clause Mod', 'Team Type Preview'],
+		ruleset: ['HP Percentage Mod', 'Switch Priority Clause Mod', 'Cancel Mod', 'Sleep Clause Mod', 'Freeze Clause Mod', 'Team Type Preview'],
 		banlist: ['Nonexistent'],
 		onModifySpecies(species, target, source, effect) {
 			if (!target) return;
@@ -4260,7 +4260,7 @@ export const Formats: import('../sim/dex-formats').FormatList = [
 		mod: 'gen3',
 		gameType: 'doubles',
 		searchShow: false,
-		ruleset: ['Standard', '!Switch Priority Clause Mod'],
+		ruleset: ['Standard'],
 		banlist: ['Uber', 'Quick Claw', 'Soul Dew', 'Explosion', 'Self-Destruct', 'Swagger'],
 		unbanlist: ['Wobbuffet', 'Wynaut'],
 	},
@@ -5165,7 +5165,7 @@ export const Formats: import('../sim/dex-formats').FormatList = [
 		name: "[Gen 3] Ubers",
 		mod: 'gen3',
 		searchShow: false,
-		ruleset: ['Standard', 'Deoxys Camouflage Clause Mod', 'One Baton Pass Clause'],
+		ruleset: ['Standard', 'One Baton Pass Clause'],
 		banlist: ['Wobbuffet + Leftovers', 'Wynaut + Leftovers', 'Baton Pass'],
 	},
 	{
@@ -5255,7 +5255,7 @@ export const Formats: import('../sim/dex-formats').FormatList = [
 		mod: 'gen3rs',
 		gameType: 'doubles',
 		searchShow: false,
-		ruleset: ['Standard', '!Switch Priority Clause Mod'],
+		ruleset: ['Standard'],
 		banlist: ['Uber', 'Quick Claw', 'Soul Dew', 'Swagger'],
 	},
 	{
@@ -5265,7 +5265,7 @@ export const Formats: import('../sim/dex-formats').FormatList = [
 		gameType: 'doubles',
 		ruleset: [
 			'Obtainable', 'Team Preview', 'Species Clause', 'Stadium Sleep Clause', 'Freeze Clause Mod', 'Max Team Size = 6', 'VGC Timer',
-			'Nickname Clause', 'Beat Up Nicknames Mod', 'Endless Battle Clause', 'Cancel Mod', 'Picked Team Size = 4', 'Exact HP Mod', 'Item Clause = 1', 'Open Team Sheets',
+			'Nickname Clause', 'Switch Priority Clause Mod', 'Beat Up Nicknames Mod', 'Endless Battle Clause', 'Cancel Mod', 'Picked Team Size = 4', 'Exact HP Mod', 'Item Clause = 1', 'Open Team Sheets',
 		],
 		banlist: ['Restricted Legendary', 'Mythical', 'Soul Dew'],
 		bestOfDefault: true,
@@ -5286,7 +5286,7 @@ export const Formats: import('../sim/dex-formats').FormatList = [
 		gameType: 'singles',
 		ruleset: [
 			'Obtainable', 'Team Preview', 'Species Clause', 'Stadium Sleep Clause', 'Freeze Clause Mod', 'Max Team Size = 6', 'VGC Timer',
-			'Nickname Clause', 'Beat Up Nicknames Mod', 'Endless Battle Clause', 'Cancel Mod', 'Picked Team Size = 3', 'Exact HP Mod', "Item Clause = 1", 'Open Team Sheets',
+			'Nickname Clause', 'Switch Priority Clause Mod', 'Beat Up Nicknames Mod', 'Endless Battle Clause', 'Cancel Mod', 'Picked Team Size = 3', 'Exact HP Mod', "Item Clause = 1", 'Open Team Sheets',
 		],
 		banlist: ['Soul Dew', 'Restricted Legendary', 'Mythical', 'Wobbuffet + Leftovers', 'Wynaut + Leftovers'],
 		restricted: [],
@@ -5372,8 +5372,8 @@ export const Formats: import('../sim/dex-formats').FormatList = [
 		ruleset: [
 			'Picked Team Size = 3', 'Min Level = 50', 'Max Level = 55', 'Max Total Level = 155',
 			'Obtainable', 'Stadium Sleep Clause', 'Freeze Clause Mod', 'Species Clause', 'Item Clause = 1',
-			'Endless Battle Clause', 'Cancel Mod', 'Event Moves Clause', 'Nickname Clause', 'Beat Up Nicknames Mod',
-			'Team Preview',
+			'Endless Battle Clause', 'Cancel Mod', 'Event Moves Clause', 'Nickname Clause', 'Switch Priority Clause Mod',
+			'Beat Up Nicknames Mod', 'Team Preview',
 		],
 		banlist: ['Uber'],
 	},
@@ -5450,7 +5450,7 @@ export const Formats: import('../sim/dex-formats').FormatList = [
 		searchShow: false,
 		ruleset: [
 			'Picked Team Size = 3', 'Min Level = 50', 'Max Level = 55', 'Max Total Level = 155',
-			'Obtainable', 'Team Preview', 'Stadium Sleep Clause', 'Species Clause', 'Nickname Clause', 'Cancel Mod', 'NC 1997 Move Legality',
+			'Obtainable', 'Switch Priority Clause Mod', 'Team Preview', 'Stadium Sleep Clause', 'Species Clause', 'Nickname Clause', 'Cancel Mod', 'NC 1997 Move Legality',
 		],
 		banlist: ['Uber'],
 	},
@@ -5477,7 +5477,7 @@ export const Formats: import('../sim/dex-formats').FormatList = [
 		desc: `Only Pokémon sets that can be rented through the American Stadium Poké Cup are legal.`,
 		mod: 'gen1stadium',
 		searchShow: false,
-		ruleset: ['Stadium Sleep Clause', 'Freeze Clause Mod', 'Species Clause', 'Nickname Clause', 'Team Preview', 'Stadium Poke Cup Rentals'],
+		ruleset: ['Stadium Sleep Clause', 'Freeze Clause Mod', 'Species Clause', 'Nickname Clause', 'Team Preview', 'Switch Priority Clause Mod', 'Stadium Poke Cup Rentals'],
 		banlist: ['Uber'],
 	},
 	{
@@ -5493,6 +5493,6 @@ export const Formats: import('../sim/dex-formats').FormatList = [
 		searchShow: false,
 		debug: true,
 		battle: { trunc: Math.trunc },
-		ruleset: ['HP Percentage Mod', 'Cancel Mod', 'Desync Clause Mod', 'Max Team Size = 24', 'Max Move Count = 24', 'Max Level = 9999', 'Default Level = 100'],
+		ruleset: ['HP Percentage Mod', 'Cancel Mod', 'Max Team Size = 24', 'Max Move Count = 24', 'Max Level = 9999', 'Default Level = 100'],
 	},
 ];
diff --git a/data/mods/gen1/rulesets.ts b/data/mods/gen1/rulesets.ts
index d6bfeaa805..ea6cc7c698 100644
--- a/data/mods/gen1/rulesets.ts
+++ b/data/mods/gen1/rulesets.ts
@@ -2,7 +2,7 @@ export const Rulesets: import('../../../sim/dex-formats').ModdedFormatDataTable
 	standardag: {
 		inherit: true,
 		ruleset: [
-			'Obtainable', 'Desync Clause Mod', 'HP Percentage Mod', 'Cancel Mod', 'Endless Battle Clause',
+			'Obtainable', 'Switch Priority Clause Mod', 'HP Percentage Mod', 'Cancel Mod', 'Endless Battle Clause',
 		],
 	},
 	standard: {
diff --git a/data/mods/gen1stadium/rulesets.ts b/data/mods/gen1stadium/rulesets.ts
index 6d81137ec5..135b6dd9f0 100644
--- a/data/mods/gen1stadium/rulesets.ts
+++ b/data/mods/gen1stadium/rulesets.ts
@@ -2,7 +2,7 @@ export const Rulesets: import('../../../sim/dex-formats').ModdedFormatDataTable
 	standardag: {
 		inherit: true,
 		ruleset: [
-			'Obtainable', 'Exact HP Mod', 'Cancel Mod',
+			'Obtainable', 'Switch Priority Clause Mod', 'Exact HP Mod', 'Cancel Mod',
 		],
 	},
 	standard: {
diff --git a/data/mods/gen2stadium2/rulesets.ts b/data/mods/gen2stadium2/rulesets.ts
index 7da1a4ed93..09e76cd416 100644
--- a/data/mods/gen2stadium2/rulesets.ts
+++ b/data/mods/gen2stadium2/rulesets.ts
@@ -2,7 +2,7 @@ export const Rulesets: import('../../../sim/dex-formats').ModdedFormatDataTable
 	standardag: {
 		inherit: true,
 		ruleset: [
-			'Obtainable', 'Team Preview', 'Exact HP Mod', 'Cancel Mod', 'Beat Up Nicknames Mod',
+			'Obtainable', 'Team Preview', 'Exact HP Mod', 'Cancel Mod', 'Switch Priority Clause Mod', 'Beat Up Nicknames Mod',
 		],
 	},
 	standard: {
diff --git a/data/mods/gen3/rulesets.ts b/data/mods/gen3/rulesets.ts
index 637f7d2197..5249c30c5c 100644
--- a/data/mods/gen3/rulesets.ts
+++ b/data/mods/gen3/rulesets.ts
@@ -5,7 +5,7 @@ export const Rulesets: import('../../../sim/dex-formats').ModdedFormatDataTable
 		desc: "The standard ruleset for all official Smogon singles tiers (Ubers, OU, etc.)",
 		ruleset: [
 			'Standard AG',
-			'Sleep Clause Mod', 'Switch Priority Clause Mod', 'Species Clause', 'Nickname Clause', 'OHKO Clause', 'Evasion Items Clause', 'Evasion Moves Clause',
+			'Sleep Clause Mod', 'Species Clause', 'Nickname Clause', 'OHKO Clause', 'Evasion Items Clause', 'Evasion Moves Clause',
 		],
 	},
 	standarddraft: {
@@ -13,7 +13,7 @@ export const Rulesets: import('../../../sim/dex-formats').ModdedFormatDataTable
 		name: 'Standard Draft',
 		desc: "The custom Draft League ruleset",
 		ruleset: [
-			'Obtainable', 'Nickname Clause', 'Beat Up Nicknames Mod', '+Unreleased', 'Sleep Clause Mod', 'OHKO Clause', 'Evasion Clause', 'Endless Battle Clause', 'HP Percentage Mod', 'Cancel Mod',
+			'Obtainable', 'Nickname Clause', 'Switch Priority Clause Mod', 'Beat Up Nicknames Mod', '+Unreleased', 'Sleep Clause Mod', 'OHKO Clause', 'Evasion Clause', 'Endless Battle Clause', 'HP Percentage Mod', 'Cancel Mod',
 			'One Boost Passer Clause', 'Freeze Clause Mod', 'Accuracy Moves Clause', 'Baton Pass Trap Clause',
 		],
 		banlist: [
diff --git a/data/mods/gen3frlg/rulesets.ts b/data/mods/gen3frlg/rulesets.ts
index 0dec9020f9..786d156bad 100644
--- a/data/mods/gen3frlg/rulesets.ts
+++ b/data/mods/gen3frlg/rulesets.ts
@@ -5,7 +5,7 @@ export const Rulesets: import('../../../sim/dex-formats').ModdedFormatDataTable
 		desc: "The standard ruleset for all official Smogon singles tiers (Ubers, OU, etc.)",
 		ruleset: [
 			'Standard AG',
-			'Sleep Clause Mod', 'Switch Priority Clause Mod', 'Species Clause', 'Nickname Clause', 'OHKO Clause', 'Evasion Items Clause', 'Evasion Moves Clause',
+			'Sleep Clause Mod', 'Species Clause', 'Nickname Clause', 'OHKO Clause', 'Evasion Items Clause', 'Evasion Moves Clause',
 		],
 	},
 	standarddraft: {
diff --git a/data/mods/gen4/rulesets.ts b/data/mods/gen4/rulesets.ts
index 71359c6c5a..d622596e3f 100644
--- a/data/mods/gen4/rulesets.ts
+++ b/data/mods/gen4/rulesets.ts
@@ -2,7 +2,7 @@ export const Rulesets: import('../../../sim/dex-formats').ModdedFormatDataTable
 	standardag: {
 		inherit: true,
 		ruleset: [
-			'Obtainable', 'HP Percentage Mod', 'Cancel Mod', 'Beat Up Nicknames Mod', 'Endless Battle Clause',
+			'Obtainable', 'HP Percentage Mod', 'Cancel Mod', 'Switch Priority Clause Mod', 'Beat Up Nicknames Mod', 'Endless Battle Clause',
 		],
 	},
 	standard: {
@@ -14,7 +14,7 @@ export const Rulesets: import('../../../sim/dex-formats').ModdedFormatDataTable
 	},
 	flatrules: {
 		inherit: true,
-		ruleset: ['Obtainable', 'Species Clause', 'Nickname Clause', 'Item Clause = 1', 'Adjust Level Down = 50', 'Picked Team Size = Auto', 'Cancel Mod'],
+		ruleset: ['Obtainable', 'Species Clause', 'Nickname Clause', 'Switch Priority Clause Mod', 'Item Clause = 1', 'Adjust Level Down = 50', 'Picked Team Size = Auto', 'Cancel Mod'],
 	},
 	teampreview: {
 		inherit: true,
diff --git a/data/rulesets.ts b/data/rulesets.ts
index 7fe0954628..27b0d154af 100644
--- a/data/rulesets.ts
+++ b/data/rulesets.ts
@@ -159,7 +159,7 @@ export const Rulesets: import('../sim/dex-formats').FormatDataTable = {
 		name: 'Standard Draft',
 		desc: "The custom Draft League ruleset",
 		ruleset: [
-			'Obtainable', 'Nickname Clause', 'Beat Up Nicknames Mod', '+Unreleased', '+CAP', 'Sketch Post-Gen 7 Moves', 'Team Preview', 'Sleep Clause Mod', 'OHKO Clause', 'Evasion Clause', 'Endless Battle Clause', 'HP Percentage Mod', 'Cancel Mod',
+			'Obtainable', 'Nickname Clause', '+Unreleased', '+CAP', 'Sketch Post-Gen 7 Moves', 'Team Preview', 'Sleep Clause Mod', 'OHKO Clause', 'Evasion Clause', 'Endless Battle Clause', 'HP Percentage Mod', 'Cancel Mod',
 		],
 		// timer: {starting: 60 * 60, grace: 0, addPerTurn: 10, maxPerTurn: 100, timeoutAutoChoose: true},
 	},
@@ -1424,30 +1424,12 @@ export const Rulesets: import('../sim/dex-formats').FormatDataTable = {
 	switchpriorityclausemod: {
 		effectType: 'Rule',
 		name: 'Switch Priority Clause Mod',
-		desc: "Makes a faster Pokémon switch first when double-switching, unlike in Emerald link battles, where player 1's Pokémon would switch first",
+		desc: "Makes a faster Pokémon switch first when double-switching, unlike in link battles, where player 1's Pokémon would switch first",
+		// Implemented in battle-queue.ts
 		onBegin() {
 			this.add('rule', 'Switch Priority Clause Mod: Faster Pokémon switch first');
 		},
 	},
-	desyncclausemod: {
-		effectType: 'Rule',
-		name: 'Desync Clause Mod',
-		desc: 'If a desync would happen, the move fails instead. This rule currently covers Bide, Counter, and Psywave.',
-		onBegin() {
-			this.add('rule', 'Desync Clause Mod: Desyncs changed to move failure.');
-		},
-		// Hardcoded in gen1/moves.ts
-		// Can't be disabled (no precedent for how else to handle desyncs)
-	},
-	deoxyscamouflageclausemod: {
-		effectType: 'Rule',
-		name: 'Deoxys Camouflage Clause Mod',
-		desc: "Reveals the Deoxys forme when it is sent in battle.",
-		// Hardcoded into effect, cannot be disabled.
-		onBegin() {
-			this.add('rule', 'Deoxys Camouflage Clause Mod: Reveals the Deoxys forme when it is sent in battle.');
-		},
-	},
 	freezeclausemod: {
 		effectType: 'Rule',
 		name: 'Freeze Clause Mod',
diff --git a/sim/battle-queue.ts b/sim/battle-queue.ts
index 59e5f80650..921070c9fc 100644
--- a/sim/battle-queue.ts
+++ b/sim/battle-queue.ts
@@ -202,6 +202,14 @@ export class BattleQueue {
 				}
 			}
 		}
+		if (this.battle.turn > 0 && !this.battle.ruleTable.has('switchpriorityclausemod') && (
+			(this.battle.gen <= 4 && action.choice === 'instaswitch') ||
+			(this.battle.gen <= 3 && action.choice === 'switch')
+		)) {
+			// Port switch priority goes: p1a, p2a, p1b, p2b
+			// Not supported: in Gen 1, each trainer sees his own Pokemon switch first
+			action.order += (action as SwitchAction).pokemon.getFieldPositionValue() / (this.battle.activePerHalf * 2);
+		}
 		if (!midTurn) {
 			if (action.choice === 'move') {
 				if (!action.maxMove && !action.zmove && action.move.beforeTurnCallback) {
diff --git a/sim/battle.ts b/sim/battle.ts
index 7a4d67aa65..9a20bfbdf5 100644
--- a/sim/battle.ts
+++ b/sim/battle.ts
@@ -1938,6 +1938,22 @@ export class Battle {
 			this.add('rated', typeof this.rated === 'string' ? this.rated : '');
 		}
 
+		if (this.gen === 1 && this.dex.currentMod !== 'gen1stadium') {
+			// If a desync would happen, the move fails instead. This rule currently covers Bide, Counter, and Psywave.
+			this.add('rule', 'Desync Clause Mod: Desyncs changed to move failure.');
+		}
+		if (this.gen === 3) {
+			// Reveals the Deoxys forme when it is sent in battle.
+			const deoxys = ['Deoxys', 'Deoxys-Attack', 'Deoxys-Defense', 'Deoxys-Speed'];
+			for (const forme of deoxys) {
+				const species = this.dex.species.get(forme);
+				if (!this.ruleTable.isBannedSpecies(species)) {
+					this.add('rule', `Deoxys Camouflage Clause${this.dex.currentMod === 'gen3colosseum' ? '' : ' Mod'}: Reveals the Deoxys forme when it is sent in battle.`);
+					break;
+				}
+			}
+		}
+
 		format.onBegin?.call(this);
 		for (const rule of this.ruleTable.keys()) {
 			if ('+*-!'.includes(rule.charAt(0))) continue;
diff --git a/test/common.js b/test/common.js
index 5cc908c283..d75bb4de75 100644
--- a/test/common.js
+++ b/test/common.js
@@ -56,6 +56,7 @@ class TestTools {
 			options.preview ? '^Team Preview' : '^!Team Preview',
 			options.sleepClause && 'Sleep Clause Mod',
 			!options.cancel && '!Cancel Mod',
+			!options.portPriority && '^Switch Priority Clause Mod',
 			options.endlessBattleClause ? '^Endless Battle Clause' : '^!Endless Battle Clause',
 			options.inverseMod && 'Inverse Mod',
 			options.overflowStatMod && 'Overflow Stat Mod',
diff --git a/test/sim/misc/turn-order.js b/test/sim/misc/turn-order.js
index 1c9a20a67a..18eddd59c8 100644
--- a/test/sim/misc/turn-order.js
+++ b/test/sim/misc/turn-order.js
@@ -185,6 +185,48 @@ describe('Switching out', () => {
 		battle.makeChoices('switch 2', 'switch 2');
 		assert.equal(battle.p2.pokemon[0].boosts.atk, 0);
 	});
+
+	describe(`Switch Priority Clause Mod [Gen 3]`, () => {
+		it('should follow speed priority if Switch Priority Clause Mod is included', () => {
+			battle = common.gen(3).createBattle({ gameType: 'doubles' }, [[
+				{ species: 'Wynaut', moves: ['sleeptalk'], evs: { spe: 0 } },
+				{ species: 'Wynaut', moves: ['sleeptalk'], evs: { spe: 4 } },
+				{ species: 'Pelipper', ability: 'drizzle', moves: ['sleeptalk'] },
+				{ species: 'Gyarados', ability: 'intimidate', moves: ['sleeptalk'] },
+			], [
+				{ species: 'Wynaut', moves: ['sleeptalk'], evs: { spe: 8 } },
+				{ species: 'Wynaut', moves: ['sleeptalk'], evs: { spe: 12 } },
+				{ species: 'Torkoal', ability: 'drought', moves: ['sleeptalk'] },
+				{ species: 'Salamence', ability: 'intimidate', moves: ['sleeptalk'] },
+			]]);
+			battle.makeChoices('switch 3, switch 4', 'switch 3, switch 4');
+			assert.equal(battle.field.weather, 'raindance');
+			assert.equal(battle.p1.active[0].boosts.atk, 0);
+			assert.equal(battle.p1.active[1].boosts.atk, 0);
+			assert.equal(battle.p2.active[0].boosts.atk, -1);
+			assert.equal(battle.p2.active[1].boosts.atk, -1);
+		});
+
+		it('should follow port priority if Switch Priority Clause Mod is excluded', () => {
+			battle = common.gen(3).createBattle({ gameType: 'doubles', portPriority: true }, [[
+				{ species: 'Wynaut', moves: ['sleeptalk'], evs: { spe: 0 } },
+				{ species: 'Wynaut', moves: ['sleeptalk'], evs: { spe: 4 } },
+				{ species: 'Pelipper', ability: 'drizzle', moves: ['sleeptalk'] },
+				{ species: 'Gyarados', ability: 'intimidate', moves: ['sleeptalk'] },
+			], [
+				{ species: 'Wynaut', moves: ['sleeptalk'], evs: { spe: 8 } },
+				{ species: 'Wynaut', moves: ['sleeptalk'], evs: { spe: 12 } },
+				{ species: 'Torkoal', ability: 'drought', moves: ['sleeptalk'] },
+				{ species: 'Salamence', ability: 'intimidate', moves: ['sleeptalk'] },
+			]]);
+			battle.makeChoices('switch 3, switch 4', 'switch 3, switch 4');
+			assert.equal(battle.field.weather, 'sunnyday');
+			assert.equal(battle.p1.active[0].boosts.atk, -1);
+			assert.equal(battle.p1.active[1].boosts.atk, -1);
+			assert.equal(battle.p2.active[0].boosts.atk, -1);
+			assert.equal(battle.p2.active[1].boosts.atk, 0);
+		});
+	});
 });
 
 describe('Switching in', () => {