diff --git a/promql/parser/generated_parser.y b/promql/parser/generated_parser.y
index 6e336e230b..cc9104cdb2 100644
--- a/promql/parser/generated_parser.y
+++ b/promql/parser/generated_parser.y
@@ -599,6 +599,13 @@ matrix_selector : expr LEFT_BRACKET positive_duration_expr RIGHT_BRACKET
 
 subquery_expr   : expr LEFT_BRACKET positive_duration_expr COLON positive_duration_expr RIGHT_BRACKET
                         {
+                        // Check if offset/@ modifiers are immediately before the subquery brackets.
+                        hasModifiers, errMsg := yylex.(*parser).hasModifiersBeforeRange($1.(Expr), $2.Pos)
+                        if hasModifiers {
+                                errRange := mergeRanges(&$2, &$6)
+                                yylex.(*parser).addParseErrf(errRange, "%s", errMsg)
+                        }
+
                         var rangeNl time.Duration
                         var stepNl time.Duration
                         if numLit, ok := $3.(*NumberLiteral); ok {
@@ -620,6 +627,13 @@ subquery_expr   : expr LEFT_BRACKET positive_duration_expr COLON positive_durati
                         }
                 | expr LEFT_BRACKET positive_duration_expr COLON RIGHT_BRACKET
                         {
+                        // Check if offset/@ modifiers are immediately before the subquery brackets.
+                        hasModifiers, errMsg := yylex.(*parser).hasModifiersBeforeRange($1.(Expr), $2.Pos)
+                        if hasModifiers {
+                                errRange := mergeRanges(&$2, &$5)
+                                yylex.(*parser).addParseErrf(errRange, "%s", errMsg)
+                        }
+
                         var rangeNl time.Duration
                         if numLit, ok := $3.(*NumberLiteral); ok {
                                 rangeNl = time.Duration(math.Round(numLit.Val*float64(time.Second)))
diff --git a/promql/parser/generated_parser.y.go b/promql/parser/generated_parser.y.go
index 4b90d757cf..23b431770a 100644
--- a/promql/parser/generated_parser.y.go
+++ b/promql/parser/generated_parser.y.go
@@ -1594,6 +1594,13 @@ yydefault:
 	case 90:
 		yyDollar = yyS[yypt-6 : yypt+1]
 		{
+			// Check if offset/@ modifiers are immediately before the subquery brackets.
+			hasModifiers, errMsg := yylex.(*parser).hasModifiersBeforeRange(yyDollar[1].node.(Expr), yyDollar[2].item.Pos)
+			if hasModifiers {
+				errRange := mergeRanges(&yyDollar[2].item, &yyDollar[6].item)
+				yylex.(*parser).addParseErrf(errRange, "%s", errMsg)
+			}
+
 			var rangeNl time.Duration
 			var stepNl time.Duration
 			if numLit, ok := yyDollar[3].node.(*NumberLiteral); ok {
@@ -1616,6 +1623,13 @@ yydefault:
 	case 91:
 		yyDollar = yyS[yypt-5 : yypt+1]
 		{
+			// Check if offset/@ modifiers are immediately before the subquery brackets.
+			hasModifiers, errMsg := yylex.(*parser).hasModifiersBeforeRange(yyDollar[1].node.(Expr), yyDollar[2].item.Pos)
+			if hasModifiers {
+				errRange := mergeRanges(&yyDollar[2].item, &yyDollar[5].item)
+				yylex.(*parser).addParseErrf(errRange, "%s", errMsg)
+			}
+
 			var rangeNl time.Duration
 			if numLit, ok := yyDollar[3].node.(*NumberLiteral); ok {
 				rangeNl = time.Duration(math.Round(numLit.Val * float64(time.Second)))
diff --git a/promql/parser/parse.go b/promql/parser/parse.go
index cefc627fda..25d34f93bf 100644
--- a/promql/parser/parse.go
+++ b/promql/parser/parse.go
@@ -1191,6 +1191,49 @@ func (p *parser) getAtModifierVars(e Node) (**int64, *ItemType, *posrange.Pos, b
 	return timestampp, preprocp, endPosp, true
 }
 
+// hasModifiersBeforeRange checks if an expression has offset/@ modifiers that are
+// immediately adjacent to a bracket (no space), which should be rejected for subqueries.
+func (*parser) hasModifiersBeforeRange(expr Expr, bracketPos posrange.Pos) (bool, string) {
+	var endPos posrange.Pos
+	var hasOffset bool
+	var hasAtModifier bool
+
+	switch e := expr.(type) {
+	case *VectorSelector:
+		endPos = e.PosRange.End
+		hasOffset = e.OriginalOffset != 0 || e.OriginalOffsetExpr != nil
+		hasAtModifier = e.Timestamp != nil
+	case *MatrixSelector:
+		vs, ok := e.VectorSelector.(*VectorSelector)
+		if !ok {
+			return false, ""
+		}
+		endPos = e.EndPos
+		hasOffset = vs.OriginalOffset != 0 || vs.OriginalOffsetExpr != nil
+		hasAtModifier = vs.Timestamp != nil
+	case *SubqueryExpr:
+		endPos = e.EndPos
+		hasOffset = e.OriginalOffset != 0 || e.OriginalOffsetExpr != nil
+		hasAtModifier = e.Timestamp != nil
+	default:
+		// Other expression types (function calls, binary ops, etc.) don't have modifiers
+		// at the selector level, so they're fine.
+		return false, ""
+	}
+
+	// Check if modifiers exist and are adjacent to the bracket (no space)
+	if endPos == bracketPos {
+		if hasOffset {
+			return true, "no offset modifiers allowed before range"
+		}
+		if hasAtModifier {
+			return true, "no @ modifiers allowed before range"
+		}
+	}
+
+	return false, ""
+}
+
 func (p *parser) experimentalDurationExpr(e Expr) {
 	if !ExperimentalDurationExpr {
 		p.addParseErrf(e.PositionRange(), "experimental duration expression is not enabled")
diff --git a/promql/parser/parse_test.go b/promql/parser/parse_test.go
index ab5564f0ff..4ad69ea76a 100644
--- a/promql/parser/parse_test.go
+++ b/promql/parser/parse_test.go
@@ -2779,6 +2779,75 @@ var testExpr = []struct {
 			},
 		},
 	},
+	// Test subquery: offset/@ modifiers immediately before subquery brackets (should error)
+	{
+		input: `some_metric offset 5m[2m:10s]`,
+		fail:  true,
+		errors: ParseErrors{
+			ParseErr{
+				PositionRange: posrange.PositionRange{Start: 21, End: 29},
+				Err:           errors.New("no offset modifiers allowed before range"),
+				Query:         `some_metric offset 5m[2m:10s]`,
+			},
+		},
+	},
+	{
+		input: `some_metric @ 123[2m:10s]`,
+		fail:  true,
+		errors: ParseErrors{
+			ParseErr{
+				PositionRange: posrange.PositionRange{Start: 17, End: 25},
+				Err:           errors.New("no @ modifiers allowed before range"),
+				Query:         `some_metric @ 123[2m:10s]`,
+			},
+		},
+	},
+	// Test subquery: matrix selector with offset/@ before subquery (should error)
+	{
+		input: `some_metric[5m] offset 1m[2m:10s]`,
+		fail:  true,
+		errors: ParseErrors{
+			ParseErr{
+				PositionRange: posrange.PositionRange{Start: 25, End: 33},
+				Err:           errors.New("no offset modifiers allowed before range"),
+				Query:         `some_metric[5m] offset 1m[2m:10s]`,
+			},
+		},
+	},
+	{
+		input: `some_metric[5m] @ 123[2m:10s]`,
+		fail:  true,
+		errors: ParseErrors{
+			ParseErr{
+				PositionRange: posrange.PositionRange{Start: 21, End: 29},
+				Err:           errors.New("no @ modifiers allowed before range"),
+				Query:         `some_metric[5m] @ 123[2m:10s]`,
+			},
+		},
+	},
+	// Test subquery: nested subquery with offset/@ before outer subquery (should error)
+	{
+		input: `some_metric[2m:10s] offset 1m[5m:1m]`,
+		fail:  true,
+		errors: ParseErrors{
+			ParseErr{
+				PositionRange: posrange.PositionRange{Start: 29, End: 36},
+				Err:           errors.New("no offset modifiers allowed before range"),
+				Query:         `some_metric[2m:10s] offset 1m[5m:1m]`,
+			},
+		},
+	},
+	{
+		input: `some_metric[2m:10s] @ 123[5m:1m]`,
+		fail:  true,
+		errors: ParseErrors{
+			ParseErr{
+				PositionRange: posrange.PositionRange{Start: 25, End: 32},
+				Err:           errors.New("no @ modifiers allowed before range"),
+				Query:         `some_metric[2m:10s] @ 123[5m:1m]`,
+			},
+		},
+	},
 	{
 		input: `(foo + bar)[5m]`,
 		fail:  true,