diff --git a/CLAUDE.md b/CLAUDE.md
index 26054d3..78ebf0b 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -65,8 +65,8 @@ les tables sauf les tables d'association.
   l'écriture).
 - **`Volunteer`** : `email` (unique **par édition**, nullable pour les
   bénévoles créés à la main — plusieurs `NULL` autorisés), `first_name`,
-  `last_name`, `phone`, `tshirt_size`, `diet`, `comment`. Pas de date de
-  naissance.
+  `last_name`, `phone`, `comment`. Pas de date de naissance, ni de taille de
+  t-shirt / régime alimentaire.
 - **`Skill`** : référentiel par édition (`code`, `label`). N-N `Volunteer`
   (`volunteer_skill`). N-N `Shift` (`shift_required_skill`).
 - **`Position`** : `name`, `location`, `category` (`PositionCategory`),
diff --git a/backend/app/api/schemas.py b/backend/app/api/schemas.py
index 6c2c363..ce4cc11 100644
--- a/backend/app/api/schemas.py
+++ b/backend/app/api/schemas.py
@@ -9,7 +9,6 @@ from app.models import (
     AssignmentSource,
     PositionCategory,
     Role,
-    TshirtSize,
 )
 from app.validation import Violation
 
@@ -49,8 +48,6 @@ class VolunteerCreate(ApiModel):
     last_name: str
     email: str | None = None
     phone: str | None = None
-    tshirt_size: TshirtSize | None = None
-    diet: str | None = None
     comment: str | None = None
     skill_codes: list[str] = Field(default_factory=list)
 
@@ -60,8 +57,6 @@ class VolunteerUpdate(ApiModel):
     last_name: str | None = None
     email: str | None = None
     phone: str | None = None
-    tshirt_size: TshirtSize | None = None
-    diet: str | None = None
     comment: str | None = None
     # None = inchangé ; [] = vider les compétences.
     skill_codes: list[str] | None = None
@@ -74,8 +69,6 @@ class VolunteerRead(ApiModel):
     last_name: str
     email: str | None
     phone: str | None
-    tshirt_size: TshirtSize | None
-    diet: str | None
     comment: str | None
     skill_codes: list[str]
     created_at: dt.datetime
diff --git a/backend/app/i18n/locales/fr.json b/backend/app/i18n/locales/fr.json
index 4ed4395..a237708 100644
--- a/backend/app/i18n/locales/fr.json
+++ b/backend/app/i18n/locales/fr.json
@@ -39,7 +39,6 @@
   "import.row.duplicate_name_in_file": "Nom et prénom déjà présents à la ligne {first_line} du fichier.",
   "import.row.updated_existing": "Bénévole existant mis à jour.",
   "import.row.possible_duplicate_name": "Un bénévole portant le même nom existe déjà dans l'édition.",
-  "import.row.invalid_tshirt_size": "Taille de t-shirt non reconnue : {value}.",
   "import.row.skill_created": "Nouvelle compétence créée : {label}.",
   "import.row.unknown_availability_value": "Valeur de disponibilité non comprise « {value} » (colonne « {column} »).",
 
diff --git a/backend/app/importing/schemas.py b/backend/app/importing/schemas.py
index e9697e6..92b2257 100644
--- a/backend/app/importing/schemas.py
+++ b/backend/app/importing/schemas.py
@@ -19,8 +19,6 @@ class ColumnMapping(BaseModel):
     last_name: str
     email: str | None = None
     phone: str | None = None
-    tshirt_size: str | None = None
-    diet: str | None = None
     comment: str | None = None
     skills: str | None = None
 
diff --git a/backend/app/importing/service.py b/backend/app/importing/service.py
index 1ed4aa4..24ee615 100644
--- a/backend/app/importing/service.py
+++ b/backend/app/importing/service.py
@@ -12,7 +12,7 @@ from app.importing.schemas import (
     RowReport,
 )
 from app.importing.text import normalize, slug_code, split_skills
-from app.importing.values import parse_availability_cell, parse_tshirt_size
+from app.importing.values import parse_availability_cell
 from app.models import (
     Availability,
     DayPart,
@@ -29,8 +29,6 @@ _FIELD_HINTS: dict[str, tuple[str, ...]] = {
     "first_name": ("prenom", "first name", "firstname", "given name"),
     "last_name": ("nom", "last name", "lastname", "surname", "famille"),
     "phone": ("tel", "phone", "portable", "mobile", "gsm"),
-    "tshirt_size": ("tshirt", "t shirt", "taille", "shirt"),
-    "diet": ("regime", "alimentaire", "diet", "allergie"),
     "comment": ("commentaire", "remarque", "note", "precision"),
     "skills": ("competence", "skill", "habilitation", "brevet", "diplome"),
 }
@@ -82,7 +80,7 @@ def validate_mapping(
                 )
             )
 
-    for field in ("email", "phone", "tshirt_size", "diet", "comment", "skills"):
+    for field in ("email", "phone", "comment", "skills"):
         header = getattr(columns, field)
         if header and header not in headers:
             errors.append(
@@ -281,25 +279,8 @@ def run_import(
             volunteer.email = email_raw or None
         if columns.phone:
             volunteer.phone = (row.get(columns.phone) or "").strip() or None
-        if columns.diet:
-            volunteer.diet = (row.get(columns.diet) or "").strip() or None
         if columns.comment:
             volunteer.comment = (row.get(columns.comment) or "").strip() or None
-        if columns.tshirt_size:
-            raw_size = (row.get(columns.tshirt_size) or "").strip()
-            if raw_size:
-                size = parse_tshirt_size(raw_size)
-                if size is None:
-                    entry.issues.append(
-                        Issue(
-                            code="import.row.invalid_tshirt_size",
-                            severity="WARNING",
-                            field="tshirt_size",
-                            params={"value": raw_size},
-                        )
-                    )
-                else:
-                    volunteer.tshirt_size = size
 
         session.flush()
 
diff --git a/backend/app/importing/values.py b/backend/app/importing/values.py
index faf2e76..484a0a6 100644
--- a/backend/app/importing/values.py
+++ b/backend/app/importing/values.py
@@ -1,7 +1,7 @@
-"""Interprétation des valeurs de cellule : disponibilités et tailles de t-shirt."""
+"""Interprétation des valeurs de cellule : disponibilités."""
 
 from app.importing.text import normalize
-from app.models import AvailabilityStatus, TshirtSize
+from app.models import AvailabilityStatus
 
 _AVAILABLE = {
     "x", "o", "oui", "y", "yes", "ok", "1", "vrai", "true",
@@ -19,18 +19,6 @@ _UNAVAILABLE = {
 }
 _EMPTY = {"", "na", "n/a", "nc"}
 
-_TSHIRT = {
-    "XS": TshirtSize.XS,
-    "S": TshirtSize.S,
-    "M": TshirtSize.M,
-    "L": TshirtSize.L,
-    "XL": TshirtSize.XL,
-    "XXL": TshirtSize.XXL,
-    "2XL": TshirtSize.XXL,
-    "XXXL": TshirtSize.XXXL,
-    "3XL": TshirtSize.XXXL,
-}
-
 
 def parse_availability_cell(value: str) -> tuple[AvailabilityStatus | None, bool]:
     """(statut, reconnu).
@@ -48,8 +36,3 @@ def parse_availability_cell(value: str) -> tuple[AvailabilityStatus | None, bool
     if norm in _UNAVAILABLE:
         return AvailabilityStatus.UNAVAILABLE, True
     return None, False
-
-
-def parse_tshirt_size(value: str) -> TshirtSize | None:
-    key = normalize(value).upper().replace(" ", "").replace("-", "")
-    return _TSHIRT.get(key)
diff --git a/backend/app/migrations/versions/0005_drop_volunteer_tshirt_diet.py b/backend/app/migrations/versions/0005_drop_volunteer_tshirt_diet.py
new file mode 100644
index 0000000..8e42e87
--- /dev/null
+++ b/backend/app/migrations/versions/0005_drop_volunteer_tshirt_diet.py
@@ -0,0 +1,38 @@
+"""Bénévole : retrait de tshirt_size et diet
+
+Revision ID: 0005_drop_volunteer_tshirt_diet
+Revises: 0004_shift_day_part
+Create Date: 2026-09-10
+
+"""
+
+from collections.abc import Sequence
+
+import sqlalchemy as sa
+from alembic import op
+
+revision: str = "0005_drop_volunteer_tshirt_diet"
+down_revision: str | None = "0004_shift_day_part"
+branch_labels: str | Sequence[str] | None = None
+depends_on: str | Sequence[str] | None = None
+
+
+_TSHIRT_SIZE = sa.Enum(
+    "XS", "S", "M", "L", "XL", "XXL", "XXXL",
+    name="tshirtsize", native_enum=False,
+)
+
+
+def upgrade() -> None:
+    op.drop_column("volunteer", "tshirt_size")
+    op.drop_column("volunteer", "diet")
+
+
+def downgrade() -> None:
+    op.add_column(
+        "volunteer", sa.Column("diet", sa.String(), nullable=True)
+    )
+    op.add_column(
+        "volunteer",
+        sa.Column("tshirt_size", _TSHIRT_SIZE, nullable=True),
+    )
diff --git a/backend/app/models/__init__.py b/backend/app/models/__init__.py
index bdfeeae..74e11ea 100644
--- a/backend/app/models/__init__.py
+++ b/backend/app/models/__init__.py
@@ -24,7 +24,6 @@ from app.models.enums import (
     AvailabilityStatus,
     PositionCategory,
     Role,
-    TshirtSize,
 )
 
 __all__ = [
@@ -43,7 +42,6 @@ __all__ = [
     "ShiftRequiredSkill",
     "Skill",
     "TimestampMixin",
-    "TshirtSize",
     "Volunteer",
     "VolunteerSkill",
     "local_now",
diff --git a/backend/app/models/domain.py b/backend/app/models/domain.py
index cb00be6..99b717e 100644
--- a/backend/app/models/domain.py
+++ b/backend/app/models/domain.py
@@ -19,7 +19,6 @@ from app.models.enums import (
     AvailabilityStatus,
     PositionCategory,
     Role,
-    TshirtSize,
 )
 
 _PASSIVE = {"passive_deletes": True}
@@ -138,11 +137,6 @@ class Volunteer(TimestampMixin, table=True):
     first_name: str
     last_name: str
     phone: str | None = None
-    tshirt_size: TshirtSize | None = Field(
-        default=None,
-        sa_column=Column(SAEnum(TshirtSize, native_enum=False), nullable=True),
-    )
-    diet: str | None = None
     comment: str | None = None
 
     skills: list[Skill] = Relationship(
diff --git a/backend/app/models/enums.py b/backend/app/models/enums.py
index 1263765..57dda53 100644
--- a/backend/app/models/enums.py
+++ b/backend/app/models/enums.py
@@ -34,13 +34,3 @@ class PositionCategory(enum.StrEnum):
     SETUP = "SETUP"
     STAGE = "STAGE"
     OTHER = "OTHER"
-
-
-class TshirtSize(enum.StrEnum):
-    XS = "XS"
-    S = "S"
-    M = "M"
-    L = "L"
-    XL = "XL"
-    XXL = "XXL"
-    XXXL = "XXXL"
diff --git a/backend/app/seed.py b/backend/app/seed.py
index c1838cc..7f8c7d2 100644
--- a/backend/app/seed.py
+++ b/backend/app/seed.py
@@ -30,7 +30,6 @@ from app.models import (
     Shift,
     ShiftRequiredSkill,
     Skill,
-    TshirtSize,
     Volunteer,
     VolunteerSkill,
 )
@@ -354,12 +353,6 @@ def build(session: Session, *, rng: random.Random | None = None) -> Summary:
             last_name=last,
             email=email,
             phone=(f"06{rng.randint(10_000_000, 99_999_999)}" if rng.random() < 0.8 else None),
-            tshirt_size=(rng.choice(list(TshirtSize)) if rng.random() < 0.9 else None),
-            diet=(
-                rng.choice(["Végétarien", "Végétalien", "Sans gluten", "Sans porc"])
-                if rng.random() < 0.25
-                else None
-            ),
         )
         session.add(volunteer)
         session.flush()
diff --git a/backend/tests/test_api_volunteers.py b/backend/tests/test_api_volunteers.py
index 0dc06e1..70179c1 100644
--- a/backend/tests/test_api_volunteers.py
+++ b/backend/tests/test_api_volunteers.py
@@ -23,14 +23,12 @@ def test_create_volunteer_with_skills(client, edition):
             "first_name": "Alex",
             "last_name": "Martin",
             "email": "alex@ex.fr",
-            "tshirt_size": "M",
             "skill_codes": ["SST", "PERMIS_B", "SST"],
         },
     )
     assert resp.status_code == 201
     body = resp.json()
     assert body["skill_codes"] == ["PERMIS_B", "SST"]
-    assert body["tshirt_size"] == "M"
     assert body["edition_id"] == str(edition.id)
 
 
diff --git a/backend/tests/test_import_service.py b/backend/tests/test_import_service.py
index 8239632..5dac763 100644
--- a/backend/tests/test_import_service.py
+++ b/backend/tests/test_import_service.py
@@ -21,7 +21,6 @@ def _mapping(dry_run: bool = False) -> ImportMapping:
             first_name="Prénom",
             last_name="Nom",
             email="Email",
-            tshirt_size="Taille",
             skills="Compétences",
         ),
         availability_columns=[
@@ -78,7 +77,6 @@ def test_happy_path_creates_volunteers_skills_and_availabilities(session, editio
 
     volunteers = {v.email: v for v in _volunteers(session, edition)}
     assert set(volunteers) == {"alex@ex.fr", "sam@ex.fr"}
-    assert volunteers["alex@ex.fr"].tshirt_size.value == "M"
     assert {s.code for s in volunteers["alex@ex.fr"].skills} == {"SST", "PERMIS_B"}
 
     avails = session.exec(
@@ -194,18 +192,6 @@ def test_invalid_email_is_skipped(session, edition):
     assert report.rows[0].issues[0].code == "import.row.invalid_email"
 
 
-def test_unknown_tshirt_size_warns_and_still_imports(session, edition):
-    report = run_import(
-        session=session,
-        edition=edition,
-        table=_table([["Alex", "Martin", "a@ex.fr", "Large", "", "x", ""]]),
-        mapping=_mapping(),
-    )
-    assert report.created == 1
-    assert report.rows[0].issues[0].code == "import.row.invalid_tshirt_size"
-    assert _volunteers(session, edition)[0].tshirt_size is None
-
-
 def test_unknown_availability_value_is_flagged(session, edition):
     report = run_import(
         session=session,
diff --git a/backend/tests/test_import_values.py b/backend/tests/test_import_values.py
index 6168ebe..9ebe121 100644
--- a/backend/tests/test_import_values.py
+++ b/backend/tests/test_import_values.py
@@ -1,8 +1,8 @@
 import pytest
 
 from app.importing.text import slug_code, split_skills
-from app.importing.values import parse_availability_cell, parse_tshirt_size
-from app.models import AvailabilityStatus, TshirtSize
+from app.importing.values import parse_availability_cell
+from app.models import AvailabilityStatus
 
 
 @pytest.mark.parametrize(
@@ -32,24 +32,6 @@ def test_unknown_cell_is_flagged():
     assert parse_availability_cell("bof") == (None, False)
 
 
-@pytest.mark.parametrize(
-    ("raw", "expected"),
-    [
-        ("M", TshirtSize.M),
-        (" m ", TshirtSize.M),
-        ("xl", TshirtSize.XL),
-        ("2XL", TshirtSize.XXL),
-        ("3 XL", TshirtSize.XXXL),
-    ],
-)
-def test_tshirt_sizes(raw, expected):
-    assert parse_tshirt_size(raw) is expected
-
-
-def test_unknown_tshirt_size_is_none():
-    assert parse_tshirt_size("large") is None
-
-
 def test_slug_code_is_stable_across_accents_and_case():
     assert slug_code("Régie son") == "REGIE_SON"
     assert slug_code(" permis B ") == "PERMIS_B"