diff --git a/engine/battle/core.asm b/engine/battle/core.asm
index 9f45c390..b5af70ce 100644
--- a/engine/battle/core.asm
+++ b/engine/battle/core.asm
@@ -170,6 +170,9 @@ StartBattle:
 	ld a, c
 	and a
 	jr z, .skipWildCatchInit
+	call IsEnemyMonSpeciesInPlayerCollection
+	and a
+	jr nz, .skipWildCatchInit
 	ld a, 1
 	ld [wWildEncounterCanCatch], a
 .skipWildCatchInit
@@ -1194,14 +1197,142 @@ EnsureEncounterCatchFlagsInitialized:
 	ret
 
 EnableEncounterCatchSRAM_Battle:
-	ld a, BANK(sMapEncounterCatchFlags)
-	call OpenSRAM
-	ret
+    ld a, BANK(sMapEncounterCatchFlags) ; should be 0 now
+    call OpenSRAM
+    ret
 
 DisableEncounterCatchSRAM_Battle:
-	call CloseSRAM
+    call CloseSRAM
+    ret
+
+; Returns non-zero if the current wild enemy species is in the player's party or PC boxes.
+IsEnemyMonSpeciesInPlayerCollection:
+	call IsEnemyMonSpeciesInPlayerParty
+	and a
+	ret nz
+	call IsEnemyMonSpeciesInAnyPlayerPCBox
+	and a
 	ret
 
+; Returns non-zero if the current wild enemy species is already present in the player's party.
+IsEnemyMonSpeciesInPlayerParty:
+	ld a, [wPartyCount]
+	ld c, a
+	ld hl, wPartySpecies
+.loop
+	ld a, c
+	and a
+	jr z, .notInParty
+	ld a, [hli]
+	ld b, a
+	ld a, [wEnemyMonSpecies]
+	cp b
+	jr z, .inParty
+	dec c
+	jr .loop
+.inParty
+	ld a, 1
+	ret
+.notInParty
+	xor a
+	ret
+
+; Returns non-zero if the current wild enemy species is present in any of the player's PC boxes.
+IsEnemyMonSpeciesInAnyPlayerPCBox:
+	ld d, 0
+.boxLoop
+	ld a, d
+	cp NUM_BOXES
+	jr z, .notInPC
+	push de
+	call IsEnemyMonSpeciesInPlayerPCBox
+	pop de
+	and a
+	jr nz, .inPC
+	inc d
+	jr .boxLoop
+.inPC
+	ld a, 1
+	ret
+.notInPC
+	xor a
+	ret
+
+; Checks one PC box.
+; in: d = box index (0 to NUM_BOXES - 1)
+; out: non-zero if the current wild enemy species exists in that box
+IsEnemyMonSpeciesInPlayerPCBox:
+    ; in:  d = box index (0..NUM_BOXES-1)
+    ; out: a = 1 if found, 0 if not
+
+    ld a, d
+    cp NUM_BOXES / 2
+    ld b, 2
+    jr c, .haveBank
+    ld b, 3
+    sub NUM_BOXES / 2
+.haveBank
+    ; a = index within half (0..5)
+    ld e, a
+    ld d, 0
+
+    ld hl, BattleBoxSRAMPointerTable
+    add hl, de
+    add hl, de
+    ld a, [hli]
+    ld h, [hl]
+    ld l, a
+
+    ; --- Open SRAM bank b safely ---
+    ld a, b
+    call OpenSRAM
+
+    ; box count
+    ld a, [hl]
+    ld c, a
+    inc hl
+
+    ; clamp
+    ld a, c
+    cp MONS_PER_BOX + 1
+    jr c, .scan
+    ld c, MONS_PER_BOX
+
+.scan
+    ld a, c
+    and a
+    jr z, .notInBox
+
+    ld a, [hli]
+    cp -1
+    jr z, .notInBox
+
+    ld b, a
+    ld a, [wEnemyMonSpecies]
+    cp b
+    jr z, .inBox
+
+    dec c
+    jr .scan
+
+.inBox
+    call CloseSRAM
+    ld a, 1
+    ret
+
+.notInBox
+    call CloseSRAM
+    xor a
+    ret
+
+BattleBoxSRAMPointerTable:
+	dw sBox1 ; sBox7
+	dw sBox2 ; sBox8
+	dw sBox3 ; sBox9
+	dw sBox4 ; sBox10
+	dw sBox5 ; sBox11
+	dw sBox6 ; sBox12
+
 ; asks if you want to use next mon
 ; stores whether you ran in C flag
 DoUseNextMonDialogue:
diff --git a/engine/items/item_effects.asm b/engine/items/item_effects.asm
index 1f6b4d34..37cd2d76 100644
--- a/engine/items/item_effects.asm
+++ b/engine/items/item_effects.asm
@@ -2669,15 +2669,12 @@ MarkWildEncounterCatchUsedItem:
     ret
 
 EnableEncounterCatchSRAM_Item:
-    ld a, $0A
-    ld [$0000], a      ; enable SRAM
-    xor a
-    ld [$4000], a      ; SRAM bank 0
+    ld a, BANK(sMapEncounterCatchFlags) ; should be 0 now
+    call OpenSRAM
     ret
 
 DisableEncounterCatchSRAM_Item:
-    xor a
-    ld [$0000], a      ; disable SRAM
+    call CloseSRAM
     ret
 
 NoCyclingAllowedHereText: